User equipment transmit duty cycle control

ABSTRACT

In some embodiments, a user equipment device (UE) implements improved communication methods which include radio resource time multiplexing, dynamic sub-frame allocation, and UE transmit duty cycle control. In some embodiments, the UE may communicate with base stations using radio frames that include multiple sub-frames, transmit information regarding allocation of a portion of the sub-frames of a respective radio frame for each of a plurality of the radio frames, and transmit and receive data using allocated sub-frames and not using unallocated sub-frames. In some embodiments, the UE may operate according to a sub-frame allocation based on its current power state. The UE may transmit information to the base station and receive the sub-frame allocation based on at least the information. In some embodiments, the UE may switch transmit duty cycles based on an occurrence of a condition at the UE. The UE may inform the network of the switch.

PRIORITY DATA

This application is a continuation of U.S. patent application Ser. No.14/834,533, titled “User Equipment Transmit Duty Cycle Control”, filedAug. 25, 2015, by Li Su, Stephan V. Schell, Jianxiong Shi, and Sami M.Almalfouh, now U.S. Pat. No. 9,854,527, and which claims benefit ofpriority to U.S. Provisional Application Ser. No. 62/043,355, titled“Radio Resource Time Multiplexing and Sub-Frame Allocation for Low PowerLTE”, filed Aug. 28, 2014, by Li Su and Stephan V. Schell, U.S.Provisional Application Ser. No. 62/100,060, titled “Sub-FrameAllocation for Low Power LTE”, filed Jan. 5, 2015 by Li Su, and U.S.Provisional Application Ser. No. 62/196,823, titled “User EquipmentTransmit Duty Cycle Control”, filed Jul. 24, 2015 by Li Su, Stephan V.Schell, Jianxiong Shi, and Sami M. Almalfouh which are all herebyincorporated by reference in their entirety as though fully andcompletely set forth herein.

The claims in the instant application are different than those of theparent application or other related applications. The Applicanttherefore rescinds any disclaimer of claim scope made in the parentapplication or any predecessor application in relation to the instantapplication. The Examiner is therefore advised that any such previousdisclaimer and the cited references that it was made to avoid, may needto be revisited. Further, any disclaimer made in the instant applicationshould not be read into or against the parent application or otherrelated applications.

FIELD

The present application relates to wireless cellular communication, andmore particularly, to methods for time multiplexing of radio resources,allocating sub-frames for reducing power consumption in a radio accesstechnology such as LTE, and controlling a transmit duty cycle of a userequipment device.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Further,wireless communication technology has evolved from voice-onlycommunications to also include the transmission of data, such asInternet and multimedia content. Therefore, improvements are desired inwireless communication. In particular, the large amount of functionalitypresent in a user equipment (UE), e.g., a wireless device such as acellular phone, can place a significant strain on the battery life ofthe UE.

In order to support LTE cellular technology in low power applications,various basic issues should be considered. First, in low powerapplications there will a limited RF range for both transmit (TX) andreceive (RX). In addition, there will be limited power, including bothlimited peak power and limited average TX power.

Further, it is desirable that any solutions to address low powerapplications be compatible/extendable to the existing LTE network,preferably with minimum to no impact on LTE NW capacity or LTE physicallayers allowing easier implementation.

Therefore, improvements in the field would be desirable.

SUMMARY

Embodiments are presented herein of, inter alia, a user equipment (UE),base station (eNB), and improved communication methods which enable a UEthat is power limited to share radio resources with other UEs.Additionally, improved communication methods which enable the UE tooperate according to a sub-frame allocation based on its power state arepresented as well as improved communication methods which enable the UEto switch between frame allocations based on current or anticipatedpower states.

Some embodiments relate to a user equipment device (UE) comprising atleast one antenna, at least one radio, and one or more processors (orone or more processing elements) coupled to the radio. The at least oneradio is configured to perform cellular communication using at least oneradio access technology (RAT). The one or more processors (or one ormore processing elements) and the at least one radio are configured toperform voice and/or data communications, as well as the methodsdescribed herein.

In some embodiments, a UE is configured to: communicate with one or morebase stations using radio frames that include multiple sub-frames,transmit information regarding allocation of a portion of the sub-framesof a respective radio frame for each of a plurality of the radio framesfor the UE, and transmit and receive data using allocated sub-frames andnot using unallocated sub-frames. In some embodiments, the allocatedsub-frames comprise portions of the sub-frames for each of the pluralityof the radio frames and the portions are less than all of the sub-framesof each respective radio frame.

In some embodiments, a method includes a UE communicating with one ormore base stations using radio frames that include multiple sub-frames,requesting allocation of a portion of the sub-frames of a respectiveradio frame for each of a plurality of the radio frames for the UE, andtransmitting and receiving data using allocated sub-frames and not usingunallocated sub-frames. In some embodiments, the allocated sub-framescomprise a portion of the sub-frames that is less than all of thesub-frames for each of the plurality of the radio frames.

In some embodiments, a base station includes a radio and a processingelement operatively coupled to the radio. In some embodiments, the radioand the processing element are configured to receive, from a UE, arequest for allocation of a portion of sub-frames for a respective radioframe of each of a plurality of radio frames, select sub-frames for therespective radio frame and allocate the selected sub-frames to the UE,and transmit data to the UE and receive data from the UE using theallocated sub-frames and not using unallocated sub-frames. In someembodiments, the allocated sub-frames make up a portion that is lessthan all of the sub-frames of the respective radio frame.

In some embodiments, the UE is configured to transmit information to thebase station and receive a sub-frame allocation from the base station.The sub-frame allocation may be based on the information. Theinformation may include one or more of a number of uplink (UL)sub-frames the UE may transmit in a frame, a number of downlink (DL)sub-frames the UE may transmit in a frame, and a minimum number ofsub-frames between transmit and receive. The UL sub-frames and/or the DLsub-frames may be contiguous. Additionally, the first information may bebased on power limitations of the UE.

In some embodiments, the UE is configured to transmit first informationto the base station indicating that the UE is in a first power state.The first power state may or may not be a power limited state. The UEmay receive a first sub-frame allocation based on at least the firstinformation from the base station and may operate according to the firstsub-frame allocation. Additionally, the UE may transmit secondinformation to the base station indicating that the UE is in, or will bein, a second power state that is different from the first power state.The UE may then receive a second sub-frame allocation, different thanthe first sub-frame allocation and may operate according to the secondsub-frame allocation.

In some embodiments, the UE is configured to operate according to afirst transmit duty cycle. The first transmit duty cycle may specify afirst number of transmissions per time period. The UE may monitor one ormore metrics associated with transmission performance of the UE anddetermine that at least one metric of the one or more metrics indicatesthat the UE needs to reduce transmissions. Additionally, the UE maydetermine a second transmit duty cycle and operate according to thesecond transmit duty cycle. The second transmit duty cycle may specify asecond number of transmissions per time period and the second number isless than the first number.

In some embodiments, the UE is configured to operate in a first stateassociated with a first transmit duty cycle and monitor a plurality ofmetrics associated with transmission performance of the UE. The firsttransmit duty cycle may specify a first number of transmissions per timeperiod. The UE may also determine that at least one metric of theplurality of metrics indicates that the UE needs to reduce transmissionsper time period and switch, based on the determination, to a secondstate associated with a second transmit duty cycle. The second transmitduty cycle may specify a second number of transmissions per time periodand may be less than the first number.

In some embodiments, the UE is configured to detect that the UE istransmitting according to a first transmit duty cycle and determine anoccurrence of at least one condition. Additionally, the UE may switchthe UE to a second transmit duty cycle in response to the determination.The first transmit duty cycle may specify a first number oftransmissions per time period and the second transmit duty cycle mayspecify a second number of transmissions per time period. The secondnumber may be less than the first number. In addition, the occurrencemay indicate that the UE needs to reduce transmissions per time period

This Summary is intended to provide a brief overview of some of thesubject matter described in this document. Accordingly, it will beappreciated that the above-described features are merely examples andshould not be construed to narrow the scope or spirit of the subjectmatter described herein in any way. Other features, aspects, andadvantages of the subject matter described herein will become apparentfrom the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtainedwhen the following detailed description of the embodiments is consideredin conjunction with the following drawings.

FIG. 1 illustrates an exemplary wireless communication system, accordingto some embodiments.

FIG. 2 illustrates a base station (“BS”, or in the context of LTE, an“eNodeB” or “eNB”) in communication with a wireless device, according tosome embodiments.

FIG. 3 illustrates a block diagram for one possible implementation of awireless communication system, according to some embodiments.

FIG. 4 illustrates a block diagram for one possible embodiment of a basestation, according to some embodiments.

FIG. 5 illustrates a diagram that shows an exemplary LTE frame,according to some embodiments.

FIGS. 6A-6C illustrate exemplary frame configurations and sub-frameallocations, according to some embodiments.

FIG. 7A illustrates a method for radio resource time multiplexing,according to some embodiments.

FIG. 7B illustrates a processor including modules for radio resourcetime multiplexing, according to some embodiments.

FIG. 8A illustrates a method for sub-frame allocation, according to someembodiments.

FIG. 8B illustrates a processor including modules for sub-frameallocation, according to some embodiments.

FIG. 9A illustrates a method for switching between frame allocations,according to some embodiments.

FIG. 9B illustrates a processor including modules for switching betweenframe allocations, according to some embodiments.

FIG. 10A illustrates state transitions for a UE, according to someembodiments.

FIG. 10B illustrates state transitions for a base station, according tosome embodiments.

FIG. 11A illustrates a method for switching between transmit dutycycles, according to some embodiments.

FIG. 11B illustrates a processor including modules for switching betweentransmit duty cycles, according to some embodiments.

FIG. 12A illustrates a method for switching between transmit dutycycles, according to some embodiments.

FIG. 12B illustrates a processor including modules for switching betweentransmit duty cycles, according to some embodiments.

FIG. 13A illustrates a method for switching between transmit dutycycles, according to some embodiments.

FIG. 13B illustrates a processor including modules for switching betweentransmit duty cycles, according to some embodiments.

FIGS. 14A-14C illustrate sub-frame allocations and ACK/NAK associationsets according to the prior art.

FIGS. 15A-15D illustrate TDD sub-frame allocations according to someembodiments.

FIGS. 16A-16D illustrate FDD sub-frame allocations according to someembodiments.

While the features described herein are susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and are herein described indetail. It should be understood, however, that the drawings and detaileddescription thereto are not intended to be limiting to the particularform disclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the subject matter as defined by the appended claims.

The term “configured to” is used herein to connote structure byindicating that the units/circuits/components include structure (e.g.,circuitry) that performs the task or tasks during operation. As such,the unit/circuit/component can be said to be configured to perform thetask even when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” language include hardware—for example, circuits,memory storing program instructions executable to implement theoperation, etc. Reciting that a unit/circuit/component is “configuredto” perform one or more tasks is expressly intended not to invoke 35U.S.C. § 112(f) for that unit/circuit/component.

DETAILED DESCRIPTION Terminology

The following is a glossary of terms used in this disclosure:

Memory Medium—Any of various types of non-transitory memory devices orstorage devices. The term “memory medium” is intended to include aninstallation medium, e.g., a CD-ROM, floppy disks, or tape device; acomputer system memory or random access memory such as DRAM, DDR RAM,SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash,magnetic media, e.g., a hard drive, or optical storage; registers, orother similar types of memory elements, etc. The memory medium mayinclude other types of non-transitory memory as well or combinationsthereof. In addition, the memory medium may be located in a firstcomputer system in which the programs are executed, or may be located ina second different computer system which connects to the first computersystem over a network, such as the Internet. In the latter instance, thesecond computer system may provide program instructions to the firstcomputer for execution. The term “memory medium” may include two or morememory mediums which may reside in different locations, e.g., indifferent computer systems that are connected over a network. The memorymedium may store program instructions (e.g., embodied as computerprograms) that may be executed by one or more processors or processingelements.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor or processing element thatexecutes instructions from a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems devices which are mobile or portable and which performs wirelesscommunications. Examples of UE devices include mobile telephones orsmart phones (e.g., iPhone™, Android™-based phones), portable gamingdevices (e.g., Nintendo DS™, Play Station Portable™, Gameboy Advance™,iPhone™), laptops, wearable devices (e.g. smart watch, smart glasses),PDAs, portable Internet devices, music players, data storage devices, orother handheld devices, etc. In general, the term “UE” or “UE device”can be broadly defined to encompass any electronic, computing, and/ortelecommunications device (or combination of devices) which is easilytransported by a user and capable of wireless communication.

Base Station—The term “Base Station” (also called “eNB”) has the fullbreadth of its ordinary meaning, and at least includes a wirelesscommunication station installed at a fixed location and used tocommunicate as part of a wireless telephone system or radio system.

Processing Element—refers to various elements or combinations ofelements. Processing elements include, for example, circuits such as anASIC (Application Specific Integrated Circuit), portions or circuits ofindividual processor cores, entire processor cores, individualprocessors, programmable hardware devices such as a field programmablegate array (FPGA), and/or larger portions of systems that includemultiple processors.

Channel—a medium used to convey information from a sender (transmitter)to a receiver. It should be noted that since characteristics of the term“channel” may differ according to different wireless protocols, the term“channel” as used herein may be considered as being used in a mannerthat is consistent with the standard of the type of device withreference to which the term is used. In some standards, channel widthsmay be variable (e.g., depending on device capability, band conditions,etc.). For example, LTE may support scalable channel bandwidths from 1.4MHz to 20 MHz. In contrast, WLAN channels may be 22 MHz wide whileBluetooth channels may be 1 MHz wide. Other protocols and standards mayinclude different definitions of channels. Furthermore, some standardsmay define and use multiple types of channels, e.g., different channelsfor uplink or downlink and/or different channels for different uses suchas data, control information, etc.

Band—The term “band” has the full breadth of its ordinary meaning, andat least includes a section of spectrum (e.g., radio frequency spectrum)in which channels are used or set aside for the same purpose.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thusthe term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

FIG. 1—Wireless Communication System

FIG. 1 illustrates a wireless cellular communication system, accordingto some embodiments. It is noted that FIG. 1 represents one possibilityamong many, and that features of the present disclosure may beimplemented in any of various systems, as desired.

As shown, the exemplary wireless communication system includes a basestation 102A which communicates over a transmission medium with one ormore wireless devices 106A, 106B, etc., through 106N. Wireless devicesmay be user devices, which may be referred to herein as “user equipment”(UE) or UE devices.

The base station 102 may be a base transceiver station (BTS) or cellsite, and may include hardware that enables wireless communication withthe UE devices 106A through 106N. The base station 102 may also beequipped to communicate with a network 100 (e.g., a core network of acellular service provider, a telecommunication network such as a publicswitched telephone network (PSTN), and/or the Internet, among variouspossibilities). Thus, the base station 102 may facilitate communicationbetween the UE devices 106 and/or between the UE devices 106 and thenetwork 100.

The communication area (or coverage area) of the base station 102 may bereferred to as a “cell.” The base station 102 and the UEs 106 may beconfigured to communicate over the transmission medium using any ofvarious radio access technologies (RATs) or wireless communicationtechnologies, such as GSM, UMTS (WCDMA, TDS-CDMA), LTE, LTE-Advanced(LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD),Wi-Fi, WiMAX etc.

Base station 102 and other similar base stations (not shown) operatingaccording to one or more cellular communication technologies may thus beprovided as a network of cells, which may provide continuous or nearlycontinuous overlapping service to UE devices 106A-N and similar devicesover a wide geographic area via one or more cellular communicationtechnologies.

Thus, while base station 102 may presently represent a “serving cell”for wireless devices 106A-N as illustrated in FIG. 1, each UE device 106may also be capable of receiving signals from one or more other cells(e.g., cells provided by other base stations), which may be referred toas “neighboring cells”. Such cells may also be capable of facilitatingcommunication between user devices and/or between user devices and thenetwork 100.

Note that at least in some instances a UE device 106 may be capable ofcommunicating using multiple wireless communication technologies. Forexample, a UE device 106 might be configured to communicate using two ormore of GSM, UMTS, CDMA2000, WiMAX, LTE, LTE-A, WLAN, Bluetooth, one ormore global navigational satellite systems (GNSS, e.g., GPS or GLONASS),one and/or more mobile television broadcasting standards (e.g., ATSC-M/Hor DVB-H), etc. Other combinations of wireless communicationtechnologies (including more than two wireless communicationtechnologies) are also possible. Likewise, in some instances a UE device106 may be configured to communicate using only a single wirelesscommunication technology.

FIG. 2 illustrates UE device 106 (e.g., one of the devices 106A through106N) in communication with base station 102. The UE device 106 may havecellular communication capability, and as described above, may be adevice such as a mobile phone, a hand-held device, a media player, acomputer, a laptop or a tablet, or virtually any type of wirelessdevice.

The UE device 106 may include a processor that is configured to executeprogram instructions stored in memory. The UE device 106 may perform anyof the method embodiments described herein by executing such storedinstructions. Alternatively, or in addition, the UE device 106 mayinclude a programmable hardware element such as an FPGA(field-programmable gate array), or other circuitry, that is configuredto perform any of the method embodiments described herein, or anyportion of any of the method embodiments described herein.

In some embodiments, the UE device 106 may be configured to communicateusing any of multiple radio access technologies and/or wirelesscommunication protocols. For example, the UE device 106 may beconfigured to communicate using one or more of GSM, UMTS, CDMA2000, LTE,LTE-A, WLAN, Wi-Fi, WiMAX or GNSS. Other combinations of wirelesscommunication technologies are also possible.

The UE device 106 may include one or more antennas for communicatingusing one or more wireless communication protocols or technologies. Insome embodiments, the UE device 106 might be configured to communicateusing a single shared radio. The shared radio may couple to a singleantenna, or may couple to multiple antennas (e.g., for MIMO) forperforming wireless communications. Alternatively, the UE device 106 mayinclude two or more radios. For example, the UE 106 might include ashared radio for communicating using either of LTE or 1×RTT (or LTE orGSM), and separate radios for communicating using each of Wi-Fi andBluetooth. Other configurations are also possible.

FIG. 3—Example Block Diagram of a UE

FIG. 3 illustrates one possible block diagram of a UE 106. As shown, theUE 106 may include a system on chip (SOC) 300, which may includeportions for various purposes. For example, as shown, the SOC 300 mayinclude processor(s) 302 which may execute program instructions for theUE 106, and display circuitry 304 which may perform graphics processingand provide display signals to the display 340. The processor(s) 302 mayalso be coupled to memory management unit (MMU) 340, which may beconfigured to receive addresses from the processor(s) 302 and translatethose addresses to locations in memory (e.g., memory 306, read onlymemory (ROM) 350, NAND flash memory 310). The MMU 340 may be configuredto perform memory protection and page table translation or set up. Insome embodiments, the MMU 340 may be included as a portion of theprocessor(s) 302.

The UE 106 may also include other circuits or devices, such as thedisplay circuitry 304, radio 330, connector I/F 320, and/or display 340.

In some embodiments, ROM 350 may include a bootloader, which may beexecuted by the processor(s) 302 during boot up or initialization. Asalso shown, the SOC 300 may be coupled to various other circuits of theUE 106. For example, the UE 106 may include various types of memory(e.g., including NAND flash 310), a connector interface 320 (e.g., forcoupling to a computer system), the display 340, and wirelesscommunication circuitry (e.g., for communication using LTE, CDMA2000,Bluetooth, WiFi, GPS, etc.).

The UE device 106 may include at least one antenna, and in someembodiments multiple antennas, for performing wireless communicationwith base stations and/or other devices. For example, the UE device 106may use antenna 335 to perform the wireless communication. As notedabove, the UE may in some embodiments be configured to communicatewirelessly using a plurality of wireless communication standards.

As described herein, the UE 106 may include hardware and softwarecomponents for implementing a method for responding to enhanced pagingaccording to embodiments of this disclosure.

The processor 302 of the UE device 106 may be configured to implementpart or all of the methods described herein, e.g., by executing programinstructions stored on a memory medium (e.g., a non-transitorycomputer-readable memory medium). In other embodiments, processor 302may be configured as a programmable hardware element, such as an FPGA(Field Programmable Gate Array), or as an ASIC (Application SpecificIntegrated Circuit).

FIG. 4—Base Station

FIG. 4 illustrates a base station 102, according to some embodiments. Itis noted that the base station of FIG. 4 is merely one example of apossible base station. As shown, the base station 102 may includeprocessor(s) 404 which may execute program instructions for the basestation 102. The processor(s) 404 may also be coupled to memorymanagement unit (MMU) 440, which may be configured to receive addressesfrom the processor(s) 404 and translate those addresses to locations inmemory (e.g., memory 460 and read only memory (ROM) 450) or to othercircuits or devices.

The base station 102 may include at least one network port 470. Thenetwork port 470 may be configured to couple to a telephone network andprovide a plurality of devices, such as UE devices 106, access to thetelephone network as described above.

The network port 470 (or an additional network port) may also oralternatively be configured to couple to a cellular network, e.g., acore network of a cellular service provider. The core network mayprovide mobility related services and/or other services to a pluralityof devices, such as UE devices 106. In some cases, the network port 470may couple to a telephone network via the core network, and/or the corenetwork may provide a telephone network (e.g., among other UE devicesserviced by the cellular service provider).

The base station 102 may include a radio 430, a communication chain 432and at least one antenna 434. The base station may be configured tooperate as a wireless transceiver and may be further configured tocommunicate with UE devices 106 via radio 430, communication chain 432and the at least one antenna 434. Communication chain 432 may be areceive chain, a transmit chain or both. The radio 430 may be configuredto communicate via various RATs, including, but not limited to, GSM,UMTS, LTE, WCDMA, CDMA2000, WiMAX, etc.

The processor(s) 404 of the base station 102 may be configured toimplement part or all of the methods described herein, e.g., byexecuting program instructions stored on a memory medium (e.g., anon-transitory computer-readable memory medium). Alternatively, theprocessor 404 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit), or a combination thereof.

Channels in LTE

LTE uses various channels so that data can be transported across the LTEradio interface. These channels are used to segregate the differenttypes of data and allow them to be transported across the radio accessnetwork in an orderly fashion. The different channels effectivelyprovide interfaces to the higher layers within the LTE protocolstructure, and enable an orderly and defined segregation of the data.

There are three categories or types of LTE data channels as follows.

Physical channels: These are transmission channels that carry user dataand control messages.

Transport channels: The physical layer transport channels offerinformation transfer to Medium Access Control (MAC) and higher layers.

Logical channels: Provide services for the Medium Access Control (MAC)layer within the LTE protocol structure.

LTE defines a number of physical downlink channels to carry informationfrom the base station to the UE. The LTE downlink comprises a physicaldownlink shared channel (PDSCH) and a physical downlink control channel(PDCCH). The PDSCH is the downlink channel that carries all user dataand all signaling messages. The PDSCH is the main data bearing channelwhich is allocated to users on a dynamic and opportunistic basis. ThePDCCH carries the layer one control for the shared channel. Thus, thePDSCH is the key channel for communicating information to the UE, andthe PDCCH communicates metadata for the information, e.g., “who” thedata is for, “what” data is sent, and “how” the data is sent over theair in the PDSCH.

LTE also defines a number of physical uplink channels to carryinformation from the UE to the base station. The LTE uplink comprises aphysical uplink shared channel (PUSCH) and a physical uplink controlchannel (PUCCH). The PUSCH is the uplink counterpart to the PDSCH. ThePUCCH provides the various control signaling requirements for uplinkcommunications. For example, the PUCCH is used for DL acknowledge/notacknowledge (ACK/NACK). Additionally, the PUCCH is used for periodicallytransmission of DL channel quality index (CQI), scheduling requests(SR), and sounding reference signals (SRS).

As described above, in LTE the base station (eNB) assigns UL resourcesusing the PDCCH, wherein this assignment of resources is called a ULgrant. The UL grant may be a type of persistent UL grant such as asemi-persistent scheduling (SPS) UL grant. The persistent orsemi-persistent UL grant may be configured by radio resource control(RRC) layer signaling and the UE may be configured with SPS by the basestation, and then the base station may activate the UE to use SPS.Persistent or semi-persistent UL grants, such as SPS, allows for apersistent, periodic UL grant. Thus, the UE may transmit new informationperiodically without receiving a new UL grant for each transmission.Alternatively, the UL grant may be for a specified amount ofinformation, and the base station may send additional UL grants based onscheduling requests from the UE.

FIG. 5—Example LTE Frame

Various embodiments disclosed herein may utilize LTE frames and/orvariations thereof. FIG. 5 shows a diagram illustrating one example ofan LTE radio frame. As illustrated, each LTE frame covers 10 ms in thetime dimension and multiple subcarriers in the frequency dimension (thenumber of subcarriers may depend on available bandwidth). Each frameincludes 10 sub-frames which each include two slots and each slotincludes one or more resource blocks (RBs) that in turn comprise a 7×12array of seven orthogonal frequency-division multiplexing (OFDM) symbolsby 12 subcarriers. As shown, the number of subcarriers/RBs in a slot maydepend on bandwidth. Typically, a block corresponding to a particularsymbol and subcarrier is referred to as a “resource element.”

Time Multiplexing Radio Resources

Embodiments disclosed herein relate to techniques wherein multiple lowpower devices may time share radio resources on a radio access network(RAN), such as an LTE network.

Low power devices may include relatively limited power amplifiers. Forexample, when transmitting at high power, the power amplifiers in thesedevices may need time to re-charge before transmitting again. This maybe especially true in low power conditions. But, high powertransmissions may be needed for effective communication in poor radioconditions. If a given base station is serving multiple such low powerdevices, it may result in inefficient use of radio resources (e.g.,because one or more low power devices are only using their resourcespart of the time and recharging at other times).

In some embodiments, radio resources in the time dimension (e.g., LTEsub-frames) are allocated among one or more low power devices. In someembodiments, sub-frames are allocated to UEs based on their powerlimitations and/or operating conditions, which a UE may be configured tospecify, e.g., using a set of rules. UEs may be configured to specifythis information at various granularities, ranging from a single bit tolarger fields with detailed information. These techniques may improvesignal strength and allow efficient use of network capacity, in someembodiments, while allowing devices to communicate in low-power and/orpoor radio quality conditions. These techniques may allowsub-frame-allocated UEs to co-exist on the network with UEs withunlimited sub-frame allocation, in some embodiments.

FIG. 6A shows a frame for LTE frame type 2, configuration 1 and anexample sub-frame allocation for configuration 1. Time division duplexLTE (TD-LTE or LTE TDD) implementations currently use seven differentconfigurations for type 2 LTE frames (FIG. 6B, described in furtherdetail below, illustrates configuration 3). As illustrated,configuration 1 includes four sub-frames for downlink (DL or D), foursub-frames for uplink (UL or U), and two special sub-frames (S). Thespecial sub-frames may allow a guard period when switching from DL toUL. The different type 2 configurations for LTE TDD may allow dynamicadjustment of the ratio between resources allocated to downlink anduplink by switching between configurations. For example, configuration 3shown in FIG. 6B includes three UL sub-frames and five DL sub-frameswhich may be useful for DL-heavy workloads.

The example sub-frame allocation includes one UL sub-frame and three DLsub-frames, allocated to a particular UE. The unused sub-frames (thefirst, second, fourth, fifth, eighth and ninth sub-frames in theillustrated example) may be allocated to a second UE or to multipleadditional UEs.

The example sub-frame allocation of FIG. 6A may be assigned to the UEbased on a request for a sub-frame allocation, which may include one ormore rules for allocating sub-frames. The base station may selectsub-frames to allocate to the UE (e.g., based on the one or more rulesand based on sub-frames allocated to other UEs) and transmit theallocation to the UE. In some embodiments, a UE may request a sub-frameallocation based on a particular DL/UL ratio, current power conditions,and/or current radio conditions. For example, in low power and/or poorradio conditions, a UE may request a large transmit/receive duty cyclesuch as one transmit and one receive sub-frame in half duplex mode everyframe. In better power and/or radio conditions, the UE may request asmall duty cycle or no duty cycle and full duplex mode (if utilizingfrequency division, discussed below). In some embodiments, UEs incertain operating conditions may request a full, unlimited sub-frameallocation rather than allocation of a portion of sub-frames. Thus, agiven UE may switch between limited and unlimited sub-frameconfigurations in some embodiments.

In other embodiments, the UE may be configured to request allocation ofa particular set of sub-frames from the base station. However, theseembodiments may be less efficient as they may not allow the base stationas much flexibility in allocating sub-frames among different UEs. Thus,in many embodiments, a UE may simply request allocation of a portion ofsub-frames within a frame without requesting particular sub-frames. Saidanother way, a request may be for any subset of sub-frames that is to begranted based on one or more rules, such as a desired number of DL andUL sub-frames. In various embodiments, the base station is configured tocommunicate with multiple UEs using a given LTE frame, using sub-framesallocated to the different UEs.

According to some embodiments, sub-frame allocation is shown as beingperformed among sub-frames within a frame. In other embodiments,allocation may be performed among sub-frames within a half-frame oramong sub-frames within multiple frames.

FIG. 6B shows a frame for LTE frame type 2, configuration 3 and anexample sub-frame allocation for configuration 3. As illustrated,configuration 3 allows greater DL throughput than UL throughput. In someembodiments, a UE may request a particular configuration and/orsub-frame allocation based on desired DL and/or UL bandwidth for aparticular workload. Configurations 1 and 3 are shown for exemplarypurposes, but any of various currently-available or futureconfigurations may be used in various embodiments.

FIG. 6C shows an exemplary full-duplex allocation in which sub-framesassigned to a UE are used for both DL and UL, e.g., by sharing frequencyresources. Full-duplex transmission may be used with frequency divisionduplexing (FDD) LTE. Speaking generally, the sub-frame allocationtechniques disclosed herein may be used in LTE FDD and/or LTE TDD. Insome embodiments, the UE is configured to request either half-duplex orfull-duplex allocation. For example, even when FDD is available, a UEmay request a half-duplex allocation in poor radio conditions, e.g., asshown in the example of half-duplex allocation of FDD of FIG. 6C. Agiven UE may be configured to communicate using half-duplex,full-duplex, or both (e.g., in different modes). Half-duplexcommunication may reduce insertion loss relative to full-dupleximplementations, e.g., by using a pair of switched transmit and receivefilters instead of a duplex filter.

In some embodiments, UEs may request sub-frame allocation using radioresource control (RRC) messages. In some embodiments, RRC messages areextended to include one or more fields for requesting sub-frameallocation. RRC messages may be advantageous because they benefit fromLTE radio layer two retransmission, increasing reliability. However,setup using RRC may take 50-100 ms to complete in some embodiments.

In other embodiments, UEs may request sub-frame allocation using controlelements of media access control (MAC) protocol data units (PDU). UsingMAC PDU control elements may allow for improved setup speed relative tousing RRC, but may not be as reliable as RRC.

In still other embodiments, other techniques and/or fields may be usedto request and/or confirm/deny sub-frame allocation in addition toand/or in place of RRC message and MAC PDU control elements.

In some embodiments, hybrid automatic repeat request (HARQ) techniquesmay be applied after sub-frame allocation. In LTE FDD implementations, aHARQ ACK/NACK indication for a given DL or UL sub-frame is typicallytransmitted four sub-frames later. However, sub-frame allocation mayresult in varying distances between sub-frames for a given UE.Therefore, in some embodiments, a DL ACK/NACK is transmitted on thefirst UL sub-frame N>=n+4 where n is the sub-frame in whichcorresponding DL data is transmitted. In these embodiments, an ULACK/NACK is transmitted in the first DL sub-frame N>=n+4 where n is thesub-frame in which corresponding UL data is transmitted. In theseembodiments, UL data is transmitted on the first sub-frame N>=n+4 wheren is the DL sub-frame that includes the UL grant. HARQ retransmissionbased on sub-frame allocation may improve DL and UL decodingreliability, e.g., for low power LTE devices with limited RF range.

FIG. 7A shows flow diagram illustrating a method 700 for timemultiplexing, according to some embodiments. The method shown in FIG. 7Amay be used in conjunction with any of the computer systems, devices,elements, or components disclosed herein, among other devices. Invarious embodiments, some of the method elements shown may be performedconcurrently, in a different order than shown, or may be omitted.Additional method elements may also be performed as desired. Flow beginsat block 710.

At block 710, a UE communicates with one or more base stations usingradio frames that include multiple sub-frames. For example, in someembodiments, the radio frames are LTE frames. Flow proceeds to block720.

At block 720, the UE transmits information regarding allocation of aportion of the sub-frames of a respective radio frame for each of aplurality of the radio frames for the UE. For example, the UE mayspecify a set of one or more rules associated with power limitationsand/or operating conditions and the base station may select sub-framesthat at least partially satisfy the rules. Flow proceeds to block 730.

At block 730, the UE transmits and receives data using allocatedsub-frames and not using unallocated sub-frames. In some embodiments, anbase station indicates allocated sub-frames to the UE prior to block730, e.g., by selecting sub-frames and allocating the sub-frames to theUE based on information received from the UE and/or based on sub-framesallocated to one or more other UEs. In various embodiments, the basestation is configured to allocate unallocated sub-frames to other UEs.In some embodiments, the UE is configured to communicate using theallocated sub-frames until communication is terminated or a request fora different allocation is sent. Flow ends at block 730.

FIG. 7B illustrates a processor including modules for time multiplexing,according to some embodiments. In some embodiments, radio 732 (which maybe equivalent to radio 330 described above) may be coupled to processor702 (which may be equivalent to processor(s) 302 described above). Theprocessor may be configured to perform the method described above inreference to FIG. 7A. In some embodiments, processor 702 may include oneor more modules, such as modules 711-731, and the modules may beconfigured to perform various steps of the method described above inreference to FIG. 7A. As shown, the modules may be configured asfollows.

In some embodiments, processor 702 may include a communication module711 configured to communicate (e.g., via radio 732) with one or morebase stations using radio frames that include multiple sub-frames. Forexample, in some embodiments, the radio frames are LTE frames.

In addition, processor 702 may include a first transmit module 721configured to transmit (e.g., via radio 732) information regardingallocation of a portion of the sub-frames of a respective radio framefor each of a plurality of the radio frames for the UE. For example, theUE may specify a set of one or more rules associated with powerlimitations and/or operating conditions and the base station may selectsub-frames that at least partially satisfy the rules.

Further, processor 702 may include a second transmit module 731configured to transmit and receive data (e.g., via radio 732) usingallocated sub-frames and not using unallocated sub-frames. In someembodiments, an base station may indicate allocated sub-frames to the UEprior to block 730, e.g., by selecting sub-frames and allocating thesub-frames to the UE based on information received from the UE and/orbased on sub-frames allocated to one or more other UEs. In variousembodiments, the base station may be configured to allocate unallocatedsub-frames to other UEs. In some embodiments, the UE may be configuredto communicate, via second transmit module 731, using the allocatedsub-frames until communication is terminated or a request for adifferent allocation is sent.

It is apparent for those skilled in the art that, for the particularprocesses of the modules described above (such as modules 711, 721, and731), reference may be made to the corresponding steps (such as steps710, 720, and 730, respectively) in the related process embodimentsharing the same concept and the reference is regarded as the disclosureof the related modules as well. Furthermore, processor 702 may beimplemented in software, hardware or combination thereof. Morespecifically, processor 702 may be implemented as a processing element,which includes, for example, circuits such as an ASIC (ApplicationSpecific Integrated Circuit), portions or circuits of individualprocessor cores, entire processor cores, individual processors,programmable hardware devices such as a field programmable gate array(FPGA), and/or larger portions of systems that include multipleprocessors. Additionally, processor 702 may be implemented as ageneral-purpose processor such as a CPU, and therefore each module canbe implemented with the CPU executing instructions stored in a memorywhich perform a respective step.

Sub-Frame Allocation

As disclosed above, sub-frames may be allocated among multiple UEs.Thus, low power devices may share resources within a frame. As noted,the techniques disclosed above may allow sub-frame allocated UEs toco-exist on the network with UEs with unlimited sub-frame allocation.FIG. 8A shows a flow diagram illustration of a method 800 fordetermining a sub-frame allocation, according to some embodiments. Themethod shown in FIG. 8 may be used in conjunction with any of thecomputer systems, devices, elements, or components disclosed herein,among other devices. In various embodiments, some of the method elementsshown may be performed concurrently, in a different order than shown, ormay be omitted. Additional method elements may also be performed asdesired. As shown, the method may be performed as follows.

At 810, a UE may transmit first information to a base station. The firstinformation may include a number of uplink (UL) sub-frames to betransmitted in a frame. The UL sub-frames may be contiguous. The firstinformation may also include a number of downlink (DL) sub-frames to bereceived in a frame and the DL sub-frames may be contiguous.Additionally, the information may include a minimum number of sub-framesbetween transmit and receive. In other words, the information mayinclude the number of sub-frames required by the UE between UL and DLcommunications.

The first information may be generated based on power limitations of theUE. Thus, the first information may be based on a power duty cycle ofthe UE. Further, in some embodiments, the first information may beindicated in a field of a radio resource control (RRC) connection setupmessage.

In some embodiments, the UE may transmit second information to the basestation. The second information may indicate that the UE may transmit inall UL sub-frames and receive in all DL sub-frames. In other words, thesecond information may indicate that the UE may operate according to anunlimited sub-frame allocation. Additionally, the second information maybe indicated in a field of a RRC connection setup message.

In certain embodiments, the UE may transmit third information to thebase station. The third information may indicate that the UE maytransmit in only half duplex for frequency division duplexing (FDD).

In some embodiments, the first information may be transmitted as arandom access channel (RACH) preamble sequence. Thus, the firstinformation may be determined based on the RACH preamble sequence.Further, the sub-frame locations of the RACH preamble sequence may beused to determine the first information.

The RACH preamble sequence may be defined based on the firstinformation. In other words, values of the first information may bestandardized and used to define the RACH preamble sequence. Thus, whenthe base station receives a RACH preamble sequence, the base station maydetermine the sub-frame allocation based on the standardized values offirst information. In such embodiments, the base station may combinereceived signals from defined RACH sub-frames to detect a RACH attemptfrom the UE. From the perspective of the UE, each preamble attempt maybelong to the same RACH procedure, including msg1 and msg2. Note that issome embodiments, each preamble may require additional power from the UEand may be referred to as a power-ramped preamble. Additionally, RACHmsg3 and msg4, which are transmitted and received using HARQ with atemporary C-RNTI (cell radio network temporary identity), should followthe sub-frame allocation implied from the RACH configuration used by theUE for random access.

Further, when the first information is transmitted via the RACH preamblesequence, the UE may also transmit an RRC connection setup messageincluding the first information. Additionally the RRC connection setupmessage may include the second information. Once the UE has attached tothe base station (e.g., after RRC connection is setup), the firstinformation may be stored in the base station. Additionally, the UE maysend second information, relating to a different sub-frame allocationand the second information may also be stored in the base station.

At 820, the UE may receive a first sub-frame allocation based on atleast the first information. The sub-frame allocation may be received inan RRC message. In some embodiments, the sub-frame allocation may bereceived in a MAC control element as part of a DL MAC PDU. Theallocation may be based on the availability of sub-frames that have notbeen allocated to other UEs. In embodiments in which the UE transmitssecond information indicating that the UE can transmit in all ULsub-frames and all DL sub-frames, the UE may receive a second allocationbased on at least the second information.

In certain embodiments, the first sub-frame allocation may alsoconfigure the periodicity and start location of at least one of the CQI,the SR, and the SRS to align with the first sub-frame allocation. Insome embodiments, the UE may receive the configuration of the CQI/SR/SRSin an RRC reconfigure message from the base station. Note that incertain embodiments, the existing CQI/SR/SRS periodicity configurationon PUCCH may be a multiple of the sub-frame allocation duty cycle. Thus,the CQI/SR/SRS periodicity does not need to be reconfigured and theCQI/SR/SRS transmission start location may be aligned, in some instancesautomatically, to the closest UL sub-frame in the sub-frame allocation.

In some embodiments, the UE's sub-frame allocation may be reconfiguredbased on network traffic. In other words, to better utilize radioresources, the UE may receive a new sub-frame allocation. The newsub-frame allocation may comply with the first information, but maymodify the location of the first UL or first DL within the sub-frame.

FIG. 8B illustrates a processor including modules for determining asub-frame allocation, according to some embodiments. In someembodiments, radio 832 (which may be equivalent to radio 330 describedabove) may be coupled to processor 802 (which may be equivalent toprocessor(s) 302 described above). The processor may be configured toperform the method described above in reference to FIG. 8A. In someembodiments, processor 802 may include one or more modules, such asmodules 811-821, and the modules may be configured to perform varioussteps of the method described above in reference to FIG. 8A. As shown,the modules may be configured as follows.

In some embodiments, processor 802 may include a transmit module 811configured to may transmit first information to a base station (e.g.,via radio 832). The first information may include a number of uplink(UL) sub-frames to be transmitted in a frame. The UL sub-frames may becontiguous. The first information may also include a number of downlink(DL) sub-frames to be received in a frame and the DL sub-frames may becontiguous. Additionally, the information may include a minimum numberof sub-frames between transmit and receive. In other words, theinformation may include the number of sub-frames required by the UEbetween UL and DL communications.

The first information may be generated based on power limitations of theUE. Thus, the first information may be based on a power duty cycle ofthe UE. Further, in some embodiments, the first information may beindicated in a field of a radio resource control (RRC) connection setupmessage.

In some embodiments, transmit module 811 may be further configured totransmit second information to the base station. The second informationmay indicate that the UE may transmit in all UL sub-frames and receivein all DL sub-frames. In other words, the second information mayindicate that the UE may operate according to an unlimited sub-frameallocation. Additionally, the second information may be indicated in afield of a RRC connection setup message.

In certain embodiments, transmit module 811 may be further configured totransmit third information to the base station. The third informationmay indicate that the UE may transmit in only half duplex for frequencydivision duplexing (FDD).

In some embodiments, the first information may be transmitted as arandom access channel (RACH) preamble sequence. Thus, the firstinformation may be determined based on the RACH preamble sequence.Further, the sub-frame locations of the RACH preamble sequence may beused to determine the first information.

The RACH preamble sequence may be defined based on the firstinformation. In other words, values of the first information may bestandardized and used to define the RACH preamble sequence. Thus, whenthe base station receives a RACH preamble sequence, the base station maydetermine the sub-frame allocation based on the standardized values offirst information. In such embodiments, the base station may combinereceived signals from defined RACH sub-frames to detect a RACH attemptfrom the UE. From the perspective of the UE, each preamble attempt maybelong to the same RACH procedure, including msg1 and msg2. Note that issome embodiments, each preamble may require additional power from the UEand may be referred to as a power-ramped preamble. Additionally, RACHmsg3 and msg4, which are transmitted and received using HARQ with atemporary C-RNTI (cell radio network temporary identity), should followthe sub-frame allocation implied from the RACH configuration used by theUE for random access.

Further, when the first information is transmitted via the RACH preamblesequence, the UE may also transmit an RRC connection setup messageincluding the first information. Additionally the RRC connection setupmessage may include the second information. Once the UE has attached tothe base station (e.g., after RRC connection is setup), the firstinformation may be stored in the base station. Additionally, the UE maysend second information, relating to a different sub-frame allocationand the second information may also be stored in the base station.

In addition, processor 820 may include a receive module 821 configuredto receive (e.g., via radio 832) a first sub-frame allocation based onat least the first information. The sub-frame allocation may be receivedin an RRC message. In some embodiments, the sub-frame allocation may bereceived in a MAC control element (CE) as part of a DL MAC PDU. Theallocation may be based on the availability of sub-frames that have notbeen allocated to other UEs. In embodiments in which the UE transmitssecond information indicating that the UE can transmit in all ULsub-frames and all DL sub-frames, the UE may receive a second allocationbased on at least the second information.

In certain embodiments, the first sub-frame allocation may alsoconfigure the periodicity and start location of at least one of the CQI,the SR, and the SRS to align with the first sub-frame allocation. Insome embodiments, the UE may receive the configuration of the CQI/SR/SRSin an RRC reconfigure message from the base station. Note that incertain embodiments, the existing CQI/SR/SRS periodicity configurationon PUCCH may be a multiple of the sub-frame allocation duty cycle. Thus,the CQI/SR/SRS periodicity does not need to be reconfigured and theCQI/SR/SRS transmission start location may be aligned, in some instancesautomatically, to the closest UL sub-frame in the sub-frame allocation.

In some embodiments, the UE's sub-frame allocation may be reconfiguredbased on network traffic. In other words, to better utilize radioresources, the UE may receive a new sub-frame allocation. The newsub-frame allocation may comply with the first information, but maymodify the location of the first UL or first DL within the sub-frame.

It is apparent for those skilled in the art that, for the particularprocesses of the modules described above (such as modules 811 and 821),reference may be made to the corresponding steps (such as steps 810 and820, respectively) in the related process embodiment sharing the sameconcept and the reference is regarded as the disclosure of the relatedmodules as well. Furthermore, processor 802 may be implemented insoftware, hardware or combination thereof. More specifically, processor802 may be implemented as a processing element, which includes, forexample, circuits such as an ASIC (Application Specific IntegratedCircuit), portions or circuits of individual processor cores, entireprocessor cores, individual processors, programmable hardware devicessuch as a field programmable gate array (FPGA), and/or larger portionsof systems that include multiple processors. Additionally, processor 802may be implemented as a general-purpose processor such as a CPU, andtherefore each module can be implemented with the CPU executinginstructions stored in a memory which perform a respective step.

Switching Between Frame Allocations

In various embodiments, it may be advantageous for a UE to switchbetween being a limited sub-frame allocated UE to a UE with unlimitedsub-frame allocation. For example, when a UE is in a good radiocondition and/or a low power condition (e.g., near a cell or basestation) the UE may operate in a first power state (e.g., a not powerlimited state) and communicate according to a sub-frame allocation basedon the first power state, whereas, when the UE enters a poor radiocondition and/or high power condition, the UE may switch to operate in asecond power state (e.g., in a state where power is restricted to beless than normal power) and communicate according to a sub-frameallocation based on the power limited state (e.g., a limited sub-frameallocation). FIG. 9A shows a flow diagram illustration of a method 900for switching between frame allocations, according to some embodiments.The method shown in FIG. 9A may be used in conjunction with any of thecomputer systems, devices, elements, or components disclosed herein,among other devices. In various embodiments, some of the method elementsshown may be performed concurrently, in a different order than shown, ormay be omitted. Additional method elements may also be performed asdesired. As shown, the method 900 may be performed as follows.

At 910, the UE may transmit first information to the base station. Thefirst information may indicate that the UE is in a first power state.The first power state may be a limited power state or may not be alimited power state. Note that when a UE is in a power state that is nota limited power state means that the power of the UE is restricted lessthan when the UE is in the limited power state. Thus, a limited powerstate means the UE is more power restricted than in another power state.

As described above, when the first power state is a limited power state,the first information may include one or more parameters such as anumber of UL sub-frames the UE may transmit in a frame, a number of DLsub-frames the UE may transmit in a frame, and a number of sub-framesbetween the UL and DL sub-frames.

At 920, the UE may receive a first sub-frame allocation based on atleast the first information. The first sub-frame allocation may indicatewhich sub-frames the UE may transmit and receive in. More particularly,when the first power state is a limited power state, the first sub-frameallocation may indicate the first UL sub-frame the UE may transmit in orthe first DL sub-frame the UE may receive in. In addition, when thefirst power state is not a limited power state (e.g., the power of theUE is restricted less than in the limited power state) the firstsub-frame allocation may indicate the UE is not limited as to whichsub-frames the UE may transmit and receive on. The UE may receive thefirst sub-frame allocation in an RRC reconfigure message and/or in a MACcontrol element as part of a DL MAC PDU.

At 930, the UE may operate according to the first sub-frame allocation.In other words, the UE may communicate with the base station using thesub-frames allocated by the first sub-frame allocation. Thus the UE maytransmit in the allocated UL sub-frame(s) and may receive in theallocated DL sub-frame(s).

At 940, the UE may transmit second information indicating that the UEis, or will be, in a second power state that is different from the firstpower state. The second power state may or may not be power limited. Ifthe first power state was a power limited state, the UE may transmit thesecond information in a sub-frame that was not allocated to the UE. Insuch instances, the second information may be transmitted in a schedulerequest (SR) signal on the PUCCH. After transmitting the secondinformation, the UE may listen on all DL sub-frames, including DLsub-frames not allocated to the UE. Further, the UE may receive an ULgrant on a sub-frame not allocated to the UE.

Additionally, the UE may transmit the second information in an RRCmessage to the base station on a UL sub-frame allocated to the UE.Alternatively, the UE may transmit the second information in a mediumaccess control (MAC) control element as part of a UL MAC packet dataunit (PDU). Further, the UE may receive an UL grant on a sub-frame notallocated to the UE.

Further, when the first power state is not a limited power state, priorto transmitting the second information, the UE may determine that thecurrent power has dropped below a threshold. Alternatively, or inaddition to, the UE may determine that the current radio conditions arebelow a radio condition threshold. In some embodiments, the UE maydetermine that power needs to be conserved for a maximum peak powertransmission in the near future prior to transmitting the secondinformation. In other words, although the UE is currently not in a powerlimited state, the UE may send the second information so the UE mayswitch to a sub-frame allocation corresponding to a power limited statein order to conserve power for a future transmission.

At 950, the UE may receive a second sub-frame allocation based on atleast the second information. As described above, when the first powerstate is a limited power state, the second sub-frame allocation may bereceived on a sub-frame not allocated to the UE. Further, the secondallocation may not limit the UE to specified sub-frames. In other words,the UE may use all UL/DL sub-frames. The UE may receive the secondsub-frame allocation in an RRC reconfigure message and/or in a MACcontrol element as part of a DL MAC PDU.

Additionally, when the first power state is not a limited power state,the second sub-frame allocation may indicate which sub-frames the UE maytransmit and receive in. More particularly, the second sub-frameallocation may indicate the first UL sub-frame the UE may transmit in orthe first DL sub-frame the UE may receive in.

At 960, the UE may operate according to the second sub-frame allocation.Thus, the UE may operate according to an unlimited allocation ofsub-frames. In other words, the UE may communicate with the base stationusing the sub-frames allocated by the second sub-frame allocation.

In further embodiments, a UE may not be operating in a power limitedstate and transmit using a maximum peak. In response, the UE may switchto a power limited state. However, due to a lack of power, the UE may beunable to currently transmit information to the base station indicatingthe power state of the UE. In such instances, the UE may not transmitfor a specified number of sub-frames. The non-transmission for thespecified number of sub-frames may be an indication of the low powerstate of the UE. Thus, the base station may determine that the UE is ina power limited state after the specified number of sub-frames hasoccurred without a transmission from the UE. The UE may then receive anRRC message containing a sub-frame allocation based on the low powerstate of the UE. The UE may then operate according to the sub-frameallocation received in the RRC message.

FIG. 9B illustrates a processor including modules for switching betweenframe allocations, according to some embodiments. In some embodiments,radio 932 (which may be equivalent to radio 330 described above) may becoupled to processor 902 (which may be equivalent to processor(s) 302described above). The processor may be configured to perform the methoddescribed above in reference to FIG. 9A. In some embodiments, processor902 may include one or more modules, such as modules 911-961, and themodules may be configured to perform various steps of the methoddescribed above in reference to FIG. 9A. As shown, the modules may beconfigured as follows.

In some embodiments, processor 902 may include a first transmit moduleconfigured to transmit (e.g., via radio 932) first information to thebase station. The first information may indicate that the UE is in afirst power state. The first power state may be a limited power state ormay not be a limited power state. As described above, when the firstpower state is a limited power state, the first information may includeone or more parameters such as a number of UL sub-frames the UE maytransmit in a frame, a number of DL sub-frames the UE may transmit in aframe, and a number of sub-frames between the UL and DL sub-frames.

In addition, processor 902 may include a first receive module 921configured to receive (e.g., via radio 932) a first sub-frame allocationbased on at least the first information. The first sub-frame allocationmay indicate which sub-frames the UE may transmit and receive in. Moreparticularly, when the first power state is a limited power state, thefirst sub-frame allocation may indicate the first UL sub-frame the UEmay transmit in or the first DL sub-frame the UE may receive in. Inaddition, when the first power state is not a limited power state (e.g.,the power of the UE is restricted less than in the limited power state)the first sub-frame allocation may indicate the UE is not limited as towhich sub-frames the UE may transmit and receive on. The UE may receivethe first sub-frame allocation in an RRC reconfigure message and/or in aMAC CE as part of a DL MAC PDU.

Processor 902 may also include a first operate module 931 configured tooperate the UE according to the first sub-frame allocation. In otherwords, the UE may communicate with the base station using the sub-framesallocated by the first sub-frame allocation. Thus the UE may transmit inthe allocated UL sub-frame(s) and may receive in the allocated DLsub-frame(s).

Processor 902 may include a second transmit module 941 configured totransmit (e.g., via radio 932) second information indicating that the UEis, or will be, in a second power state that is different from the firstpower state. The second power state may or may not be power limited. Ifthe first power state was a power limited state, the UE may transmit thesecond information in a sub-frame that was not allocated to the UE. Insuch instances, the second information may be transmitted in a schedulerequest (SR) signal on the PUCCH. After transmitting the secondinformation, the UE may listen on all DL sub-frames, including DLsub-frames not allocated to the UE. Further, the UE may receive an ULgrant on a sub-frame not allocated to the UE.

Additionally, the UE may transmit the second information in an RRCmessage to the base station on a UL sub-frame allocated to the UE.Alternatively, the UE may transmit the second information in a mediumaccess control (MAC) control element as part of a UL MAC packet dataunit (PDU). Further, the UE may receive an UL grant on a sub-frame notallocated to the UE.

Further, when the first power state is not a limited power state, priorto transmitting the second information, the UE may determine that thecurrent power has dropped below a threshold. Alternatively, or inaddition to, the UE may determine that the current radio conditions arebelow a radio condition threshold. In some embodiments, the UE maydetermine that power needs to be conserved for a maximum peak powertransmission in the near future prior to transmitting the secondinformation. In other words, although the UE is currently not in a powerlimited state, the UE may send the second information so the UE mayswitch to a sub-frame allocation corresponding to a power limited statein order to conserve power for a future transmission.

Additionally, processor 902 may include a second receive module 951configured to receive (e.g., via radio 932) a second sub-frameallocation based on at least the second information. As described above,when the first power state is a limited power state, the secondsub-frame allocation may be received on a sub-frame not allocated to theUE. Further, the second allocation may not limit the UE to specifiedsub-frames. In other words, the UE may use all UL/DL sub-frames. The UEmay receive the second sub-frame allocation in an RRC reconfiguremessage and/or in a MAC control element as part of a DL MAC PDU.

Additionally, when the first power state is not a limited power state,the second sub-frame allocation may indicate which sub-frames the UE maytransmit and receive in. More particularly, the second sub-frameallocation may indicate the first UL sub-frame the UE may transmit in orthe first DL sub-frame the UE may receive in.

Processor 902 may also include a second operate module 961 configured tooperate the UE according to the second sub-frame allocation. Thus, theUE may operate according to an unlimited allocation of sub-frames. Inother words, the UE may communicate with the base station using thesub-frames allocated by the second sub-frame allocation.

In further embodiments, a UE may not be operating in a power limitedstate and transmit using a maximum peak. In response, the UE may switchto a power limited state. However, due to a lack of power, the UE may beunable to currently transmit information to the base station indicatingthe power state of the UE. In such instances, the UE may not transmitfor a specified number of sub-frames. The non-transmission for thespecified number of sub-frames may be an indication of the low powerstate of the UE. Thus, the base station may determine that the UE is ina power limited state after the specified number of sub-frames hasoccurred without a transmission from the UE. The UE may then receive anRRC message containing a sub-frame allocation based on the low powerstate of the UE. The UE may then operate according to the sub-frameallocation received in the RRC message.

It is apparent for those skilled in the art that, for the particularprocesses of the modules described above (such as modules 911, 921, 931,941, 951, and 961), reference may be made to the corresponding steps(such as steps 910, 920, 930, 940, 950, and 960, respectively) in therelated process embodiment sharing the same concept and the reference isregarded as the disclosure of the related modules as well. Furthermore,processor 902 may be implemented in software, hardware or combinationthereof. More specifically, processor 902 may be implemented as aprocessing element, which includes, for example, circuits such as anASIC (Application Specific Integrated Circuit), portions or circuits ofindividual processor cores, entire processor cores, individualprocessors, programmable hardware devices such as a field programmablegate array (FPGA), and/or larger portions of systems that includemultiple processors. Additionally, processor 802 may be implemented as ageneral-purpose processor such as a CPU, and therefore each module canbe implemented with the CPU executing instructions stored in a memorywhich perform a respective step.

Transmit Duty Cycle Management

As disclosed above, sub-frames may be allocated among multiple UEs viatime multiplexing. Thus, low power devices may share resources within aframe. In addition, the techniques disclosed above may allow sub-frameallocated UEs to co-exist on the network with UEs with unlimitedsub-frame allocation. Further, techniques disclosed above may allow a UEto have different sub-frame allocations based on various factors.Additionally, a UE may switch between being a limited sub-frameallocated UE to a UE with unlimited sub-frame allocation depending oncircumstances associated with the UE.

In some scenarios, a UE may have a link budget constraint (orlimitation) compared to typical UEs. For example, a UE may have a linkbudget constrained by 10-15 dB as compared to typical UEs. In otherwords, a UE may be power constrained in some way that may affect itslink budget, e.g., due to signal conditions, antenna size and/or powerrequirements, and/or battery charge. Note that these conditions mayoccur at the UE at varying times and/or in any combination. In someinstances, due to the link budget constraint, the UE may need to operateat a higher peak transmit power (e.g., 23 dBm peak transmit power). Thehigher peak transmit power may not limit the UE if a battery of the UEhas a full chemical charge (e.g., has a fully charged battery), or anear full chemical charge, however, as the battery of the UE discharges(i.e., as the chemical charge of the battery dissipates over time), theUE may not be able to maintain the higher peak transmit powercontinuously. Additionally, continuous transmission at the higher peaktransmit power may result increased operating temperatures for the UE(i.e., an increased thermal load on the UE that may require mitigationto protect components of the UE). In both instances, the UE may need tolimit transmissions at the higher peak transmit power. In other words,the UE may not be able to transmit continuously at the higher peaktransmit power in all conditions. Thus, the transmit duty cycle may needto be altered or throttled under certain conditions.

In some embodiments, a UE may alter a transmit duty cycle based onbattery charge state, radio conditions, and/or thermal conditions. Notethat the transmit duty cycle may be applied to uplink transmissions andthe UE may receive all scheduled downlink communications, according tosome embodiments. Additionally, the UE may autonomously manage thetransmit duty cycle. In other words, changing of the transmit duty cyclemay be managed at the UE and not driven (managed) by a network. In someembodiments, the UE may attempt to minimize impact of changing thetransmit duty cycle on network key performance indicators (KPI) viamessaging with the network explicitly indicating a change in transmitduty cycle and by implicitly excising discontinuous transmission (DTX)pattern.

In some embodiments, the UE may control a transmit duty cycle for aphysical uplink shared channel (PUSCH) and/or a physical uplink controlchannel (PUCCH). The UE may locally control the transmit duty cycle andmay additionally control a peak power transmit duty cycle. The UE mayuse a transmit duty cycle for thermal reasons and a peak power transmitcycle for peak power reasons. In some embodiments, the UE may have twotransmit duty cycle states. In a first state (e.g., a normal state, theUE may operate without transmit duty cycle control. In other words, theUE may not limit transmissions in the first state. In a second state(e.g., a restricted state) the UE may limit transmissions based on atransmit duty cycle. For example, for buffer status report triggereduplink (UL) grants, the UE may send a target transmit duty cycle limitedUL BSR to the network which may result in throttled BSR triggered ULgrants for data and/or VoLTE transmissions. As another example, forunsolicited UL grants, such as periodic UL grants for VoLTE, the UE mayblank transmissions or use a DTX pattern along with various mitigationmethods (e.g., setting the transmit duty cycle to 75%, 70%, 50%, and soforth) to avoid impacting a network PDCCH outer loop. In other words, ifthe unsolicited UL grants fall outside of the target transmit duty cycleof the UE, the UE may implement the target transmit duty cycle via a DTXpattern.

In some embodiments, the UE may send a MAC control element message tothe network to inform the network of the UE's transmit duty cycle. Forexample, the UE may include a target transmit duty cycle and/or anoptional DTX pattern. In response, if the network supports UE triggeredtransmit duty cycle control, the network may schedule the UE based onthe transmit duty cycle control which may minimize the impact of the UEnot honoring some UL grants.

FIG. 10A illustrates state transitions for a UE, such as UE 106,according to embodiments and FIG. 10B illustrates state transitions fora base station, such as base station 102, according to embodiments. Thestate transitions shown in FIGS. 10A and 10B may be used in conjunctionwith any of the computer systems, devices, elements, or componentsdisclosed herein, among other devices. Additional states may also beadded as desired.

As discussed above, a UE, such as UE 106 may maintain a first state,such as state 1002. State 1002 may be associated with a normal state andthe UE may operate with a normal (or standard) duty cycle. In otherwords, the UE may not limit transmissions to a base station in state1002. Note that state 1002 may be associated with a baseband layer ofthe UE and the baseband layer of the UE may notify, via a message orindication, an application processor of the UE that the UE is in (or ismaintaining) state 1002. In addition, while maintaining state 1002, theUE may send an indication or message to a base station that the UE is in(or maintaining) state 1002. As shown in FIG. 10B, the base station maymaintain state 1012 which corresponds to state 1002. Note that althoughthe UE may send an indication to the base station, the base station maynot send a message or indication back to the UE indicating the state ofthe base station. In other words, there is no requirement forhandshaking between the base station and UE for each to maintaincorresponding states.

In some embodiments, the UE may detect a first switch event, such asswitch event 1006. Detection of switch event 1006 may cause the UE tochange (or switch) states. In other words, in response to the firstswitch event, the UE may transition from a first state (e.g., state1002) to another state, such as state 1004. State 1004 may be associatedwith a restricted state and the UE may operate with a restrictedtransmit duty cycle while in state 1004. Switch event 1006 may includeone or more conditions (or metrics) monitored locally by the UE. The oneor more conditions may include the UE monitoring multiple metrics andcomparing each of the multiple metrics to respective thresholds. Forexample, the UE may monitor a transmission blanking rate for a period oftime and compare it to a transmission blanking rate threshold and switchfrom state 1002 to state 1004 if the transmission blanking rate exceedsthe transmission blanking rate threshold. Note that the transmissionblanking rate threshold may be any of various values, such as 1%, 2%,5%, 10%, 20%, and so forth. Note additionally that the transmissionblanking rate may be based on a pre under voltage lockout (preUVLO)signal.

As another example, the UE may monitor a battery chemical charge leveland compare the battery chemical charge level to a battery chemicalcharge threshold and switch from state 1002 to state 1004 if the batterychemical charge level is less than or equal to the battery chemicalcharge threshold. Note that the battery chemical charge threshold may beany of various values, such as 5%, 10%, 15%, 20%, 25%, 30%, and soforth. In some embodiments, the UE may also monitor the rate of batterychemical charge dissipation and compare it to a battery chemical chargedissipation threshold and switch from state 1002 to state 1004 if therate of battery chemical charge dissipation exceeds the threshold. Insome embodiments, the UE may only monitor the rate of battery chemicalcharge dissipation once the battery chemical charge level drops below aspecified level (e.g., 10%, 20%, 30%, 40%, 50%, and so forth).

As yet another example, the UE may monitor audio frame error rate (FER)and compare it to a FER threshold and switch from state 1002 to state1004 if the audio FER exceeds the FER threshold. Note that the FERthreshold may be between 1% and 10%, among other values.

It should be noted that other conditions may trigger the UE to switchfrom state 1002 to state 1004. For example, the UE may switch from state1002 to state 1004 based on thermal load on various components of theUE. Thus, the UE may monitor internal temperatures of various componentsand compare the internal temperatures to respective thresholds. Inaddition, the condition that triggers the UE to switch from state 1002to state 1004 may include scenarios in which none of the monitoredconditions (e.g., metrics comparable to respective thresholds) wouldindependently trigger a switch from state 1002 to state 1004, however,in combination, indicate to the UE a need to switch from state 1002 tostate 1004. In other words, the UE may monitor multiple conditions andadjust respective thresholds (e.g., consider the threshold plus somemargin, e.g., within 1 to 10 percent of the threshold) such that switchevent 1006 is triggered based on an occurrence of multiple conditions.For example, the UE may detect that the thermal load on the UE isincreasing and the battery chemical charge is near the battery chemicalcharge threshold and/or the transmission blanking rate is near thetransmission blanking threshold and trigger switch event 1006.Alternatively, the UE may require multiple conditions to occur totrigger switch event 1006. For example, these multiple conditions mayinclude the FER rate exceeding the FER threshold and the batterychemical charge level being less than the battery chemical chargethreshold and/or the transmission blanking rate exceeding thetransmission blanking threshold.

In state 1004 the UE may operate according to a restricted transmit dutycycle. In other words, the UE may reduce transmissions within asub-frame and may blank (or skip) allocated sub-frames. For example forBSR triggered UL grants for data and/or VoLTE audio, the UE may limit aBSR report to include only data volume which would be allowed by thetransmit duty cycle target. As another example, the UE may perform adiscontinuous transmission action (e.g., blank, skip, transmit with alower transmission power, and/or not transmit) for over-allocated (interms of the transmit duty cycle) UL grants. In other words, the UE,based on the transmit duty cycle, may skip transmission for eachallocated sub-frame that does not coincide with sub-frames the UE wouldtransmit on based on the transmit duty cycle. As another example, forunsolicited UL grants periodically allocated every 20 ms/40 ms for VoLTEaudio packets, the UE may perform a discontinuous transmission actionfor UL grants above (or beyond) the transmit duty cycle target. In otherwords, if the transmit duty cycle target for the UE includestransmitting a specified number of times every 20 ms/40 ms for VoLTE,the UE may perform a discontinuous transmission action for UL grants inexcess of the specified number of times. In some embodiments, thediscontinuous transmission action may be performed with mitigationmethods as described above.

In some embodiments, the UE may send an indication to an applicationprocessor (or processor) of the UE upon switching to (or whilemaintaining) state 1004. In response, the processor may proactivelylimit (or throttle) certain hardware components (e.g., displaybrightness, heart beat rate monitor, and so forth) prior to a datapacket transmission session, such as a VoLTE call, starting.Alternatively, or in addition, the processor may reactively limit (orthrottle) certain hardware components during the data packettransmission session.

In some embodiments, if a transmission blanking rate is greater than athreshold, the UE may send a MAC CE to the base station. The MAC CE mayinclude information regarding the transmit duty cycle. The informationmay include an indication of the transmit duty cycle. The indication maybe an optional discontinuous transmission pattern that the UE is using(e.g., a discontinuous transmission pattern that aligns with thetransmit duty cycle of the UE). The MAC CE may be sent multiple timesover multiple frames. In other words, the UE may send the MAC CE to thenetwork N times with a periodicity of M milliseconds.

In some embodiments, the UE may detect a second switch event, such asswitch event 1008. Detection of switch event 1008 may cause the UE tochange (or switch) states. In other words, in response to the secondswitch event, the UE may transition from the second state (e.g., state1004) to another state, such as state 1002. Switch event 1008 mayinclude one or more conditions (or metrics) monitored locally by the UE.The one or more conditions may include the UE monitoring multiplemetrics and comparing each of the multiple metrics to respectivethresholds. In some embodiments, the respective thresholds may beassociated with switch event 1008. In other words, the respectivethresholds associated with switch event 1008 may be independent of,and/or distinct from, respective thresholds associated with switch event1006. Alternatively, respective thresholds associated with switch event1008 may correspond to (or be based at least in part on and/or afunction of) respective thresholds associated with switch event 1006.

For example, in some embodiments, the UE may monitor transmissionblanking rate while in (or maintaining) state 1004 and may compare thetransmission blanking rate to a transmission blanking threshold and maytrigger switch event 1008 if the transmission blanking rate is below thetransmission blanking threshold. In some embodiments, the transmissionblanking threshold used to trigger switch event 1008 may be distinctfrom (and/or independent of) the transmission blanking threshold used totrigger switch event 1006. In other embodiments, the transmissionblanking thresholds may be related, e.g., equivalent, a function of oneanother, or one threshold may be based at least in part on thecorresponding threshold. Note that the transmission blanking ratethreshold may be any of various values, such as 1%, 2%, 5%, 10%, 20%,and so forth. Note additionally that the transmission blanking rate maybe based on a pre under voltage lockout (preUVLO) signal.

As another example, the UE may monitor a battery chemical charge leveland compare the battery chemical charge level to a battery chemicalcharge threshold and switch from state 1004 to state 1002 (i.e., triggerswitch event 1008) if the battery chemical charge level is greater thanor equal to the battery chemical charge threshold. Note that the batterychemical charge threshold may be any of various values, such as 5%, 10%,15%, 20%, 25%, 30%, 35%, 40% and so forth. In some embodiments, the UEmay also monitor the rate of battery chemical charge and compare it to abattery chemical charge threshold and switch from state 1002 to state1004 if the rate of battery chemical charge exceeds the threshold. Insome embodiments, the UE may only monitor the rate of battery chemicalcharge once the battery chemical charge level drops below a specifiedlevel (e.g., 10%, 20%, 30%, 40%, 50%, and so forth).

As yet another example, the UE may monitor audio frame error rate (FER)and compare it to FER threshold and switch from state 1004 to state 1002if the audio FER is less than the FER threshold. Note that the FERthreshold may be between 1% and 10%, among other values.

In some embodiments, the UE may trigger switch event 1008 if the currenttransmit duty cycle is less a transmit duty cycle threshold.Additionally, in some embodiments, the UE may trigger switch event 1008if a packet data convergence protocol (PDCP) pending data volume is lessthan a PDCP pending data threshold.

It should be noted that other conditions may trigger the UE to switchfrom state 1004 to state 1002. For example, the UE may switch from state1004 to state 1002 based on thermal load on various components of theUE. Thus, the UE may monitor internal temperatures of various componentsand compare the internal temperatures to respective thresholds. Inaddition, the condition that triggers the UE to switch from state 1004to state 1002 may include scenarios in which none of the monitoredconditions (e.g., metrics comparable to respective thresholds) wouldindependently trigger a switch from state 1004 to state 1002, however,in combination, indicate to the UE that it may switch from state 1004 tostate 1002. In other words, the UE may monitor multiple conditions andadjust respective thresholds (e.g., consider the threshold less somemargin, e.g., within 1 to 10 percent of the threshold) such that switchevent 1008 is triggered based on an occurrence of multiple conditions.For example, the UE may detect that the thermal load on the UE isdecreasing and the battery chemical charge is near the battery chemicalcharge threshold and/or the transmission blanking rate is near thetransmission blanking threshold and trigger switch event 1006.Alternatively, the UE may require multiple conditions to occur totrigger switch event 1006. For example, the FER rate is less than theFER threshold and the battery chemical charge level is greater than thebattery chemical charge threshold and/or the transmission blanking rateis less than the transmission blanking threshold.

After switch event 1008 has been triggered, the UE may return to state1002 and may discontinue (or stop) local transmit duty cycle control. Inother words, the UE may discontinue restricting UL transmissions.Additionally, the UE may send a MAC CE to the base station including anindication the UE has returned to normal operation (i.e., the UE is nolonger limiting UL transmissions locally). The MAC CE may be sentmultiple times over multiple frames. In other words, the UE may send theMAC CE to the network N times with a periodicity of M milliseconds. Notethat the network may or may not allocate all requested UL grants as perthe UE's desired normal transmit duty cycle.

Additionally, in some embodiments, the UE may send an indication to theapplication processor (or processor) of the UE that the UE is in state1002. In response, the processor may discontinue limiting (orthrottling) certain hardware components.

As noted above, FIG. 10B illustrates state transitions for a basestation, such as base station 102, according to embodiments. A basestation may maintain a first state, such as state 1012 that correspondsto state 1002 of the UE. As noted above, the UE may send an indication(e.g., a MAC control element) to the base station that the UE ismaintaining (or operating in or switching to) state 1004. The indicationmay cause the base station to switch from state 1012, which correspondsto state 1002 of the UE, to state 1014, which corresponds to state 1004of the UE. In other words, if the base station is operating in state1012, the indication the UE sends while operating in state 1004 maycause switch event 1016. In some embodiments, the UE may send theindication in response to switch event 1006. Similarly, the base stationmay maintain state 1014, corresponding to state 1004, and may receive anindication from the UE that the UE is maintaining (or operating in orswitching to) state 1002. The indication may cause the base station toswitch from state 1014, which corresponds to state 1004 of the UE, tostate 1012, which corresponds to state 1002 of the UE. In other words,if the base station is operating in state 1014, the indication the UEsends while operating in state 1002 may cause switch event 1018. In someembodiments, the UE may send the indication in response to switch event1008.

In some embodiments, the base station may detect the discontinuoustransmission cycle of the UE and in response, may trigger either switchevent 1020 or switch event 1022, depending on the current state of thebase station. If the base station is maintaining state 1012 and detectsa new discontinuous transmission cycle indicating that the UE has areduced transmit duty cycle, the base station may trigger switch event1020. If the base station is maintaining state 1014 and detects a newdiscontinuous transmission cycle indicating that the UE has an increasedtransmit duty cycle (e.g., a standard or normal transmit duty cycle),the base station may trigger switch event 1022.

It should be noted that whether the UE controls the transmit duty cycleor the network (base station) controls the transmit duty cycle, theresult is that the UE may extend a delay time for an UL packet to starta first HARQ transmission. Thus, for VoLTE audio packets, the UE mayincrease audio FER due to dropping UL audio packets if the delay time isgreater than 100 ms which may reduce VoLTE link budget. Additionally, UEtransmit duty cycle control may not honor some UL grants (e.g., if theUL grants do not coincide with sub-frames the UE will transmit in basedon transmit duty cycle) which may impact the network's downlink (DL)PDCCH outer loop.

As noted above, in some embodiments, the UE may attempt to minimizeimpact of changing the transmit duty cycle on network key performanceindicators (KPI). In other words, the UE may attempt to mitigate theimpact of the transmit duty cycle on the network. In some embodiments,the UE may monitor signal-to-noise ratio (SNR) of the DL PDCCH and ifthe DL PDCCH SNR is below a PDCCH SNR threshold, the UE may implementthe transmit duty cycle. However, if the DL PDCCH SNR is above the PDCCHSNR threshold, the UE may not fully implement the transmit duty cycle tominimize impact on network KPI. For example, the UE may only blank (orskip) transmission on non-RV0 (redundancy version 0) sub-frames (e.g.,non-RV0 transmit time intervals (TTIs) in a transmit time interval block(TTIB)). As another example, the UE may excise transmissions with apower back off. Alternatively, or in addition, the UE may transmit onlower power PUCCH instead of PUSCH at peak transmit power to reduceVoLTE link budget.

In some embodiments, when a battery of a UE have a chemical charge levelgreater than or equal to 30%, it is estimated that there may be morethan a seven times reduction in preUVLOs (e.g., from 70 preUVLOs down to10), thus, the UE in such embodiments may support an LTE transmit dutycycle of 100% (i.e., continuous transmission). Thus, a normal dutycycle, according to some embodiments, may be considered a transmit dutycycle of 100%. However, when the chemical charge level of the battery isthan or equal to 10%, the UE may need to reduce transmissions and changethe transmit duty cycle. For example, when SDU FER is between 1 and 10percent (e.g., when transmit blanking rate is greater than or equal to8% and SDU FER is greater than or equal to 8% for 250 milliseconds), theUE may enter a restricted transmit duty cycle state with a maximumtransmit duty cycle of 75%. In addition, the UE may send a MAC CE to thenetwork indicating the transmit duty cycle targeted by the UE (e.g., 75%transmit duty cycle). Further, when SDU FER is less than or equal to 1%for a time period such as 500 milliseconds, the UE may enter a normaltransmit duty cycle (i.e., continuous transmission or 100%) and may senda MAC CE to the network indicating the transmit duty cycle targeted bythe UE (e.g., 100% transmit duty cycle). Additionally, or alternatively,when the chemical charge level of the battery increases to greater thanor equal to 30%, the UE may also enter a normal transmit duty cycle.(i.e., continuous transmission or 100%) and may send a MAC CE to thenetwork indicating the transmit duty cycle targeted by the UE (e.g.,100% transmit duty cycle).

FIG. 11A shows a flow diagram illustration of a method 1100 forswitching between transmit duty cycles, according to some embodiments.The method shown in FIG. 11A may be used in conjunction with any of thecomputer systems, devices, elements, or components disclosed herein,among other devices. In various embodiments, some of the method elementsshown may be performed concurrently, in a different order than shown, ormay be omitted. Additional method elements may also be performed asdesired. As shown, the method 1100 may be performed as follows.

At 1110, a UE, such as UE 106, may operate according to a first transmitduty cycle. The first transmit duty cycle may specify a first number oftransmissions per time period. The first transmit duty cycle maycorrespond to state 1002 as described above with reference to FIG. 10A.

At 1120, the UE may monitor one or more metrics associated withtransmission performance of the UE. Note that the one or more metricsmay include any of the metrics (and/or conditions) described above inreference to FIG. 10A.

At 1130, the UE may determine that the UE needs to reduce transmissionsper time period. The determination may be based at least in part on atleast one metric of the one or more metrics. In other words, the UE maydetermine that at least one of the one or more metrics indicates thatthe UE needs to reduce transmissions per time period. Note that the oneor more metrics may include any of the metrics (and/or conditions)described above in reference to FIG. 10A. Additionally, the indicationmay be based on comparison of a metric to an associated threshold asdescribed above.

At 1140, the UE may switch to a second transmit duty cycle. The secondtransmit duty cycle specifies a second number of transmissions per timeperiod. The second number may be less than the first number. The secondtransmit duty cycle may correspond to state 1004 as described above withreference to FIG. 10A.

In some embodiments, the UE may determine that at least one of metric ofthe one or more metrics indicates that the UE may increasetransmissions. Further, the UE may determine a third transmit dutycycle. The third transmit duty cycle may specify a third number oftransmissions per time period. The third number may be greater than thesecond number. In some embodiments, the third number may be equivalentto the first number. The UE may operate according to the third transmitduty cycle.

At 1150, the UE may operate according to the second transmit duty cycle.In some embodiments, the UE may transmit an indication to a base stationthat the UE is operating according to the second transmit duty cycle.

FIG. 11B illustrates a processor including modules for switching betweentransmit duty cycles, according to some embodiments. In someembodiments, radio 1132 (which may be equivalent to radio 330 describedabove) may be coupled to processor 1102 (which may be equivalent toprocessor(s) 302 described above). The processor may be configured toperform the method described above in reference to FIG. 11A. In someembodiments, processor 1102 may include one or more modules, such asmodules 1111-1151, and the modules may be configured to perform varioussteps of the method described above in reference to FIG. 11A. As shown,the modules may be configured as follows.

In some embodiments, processor 1102 may include a first operate module1111 configured to operate the UE according to a first transmit dutycycle. The first transmit duty cycle may specify a first number oftransmissions per time period. The first transmit duty cycle maycorrespond to state 1002 as described above with reference to FIG. 10A.

Processor 1102 may also include monitor module 1121 configured tomonitor one or more metrics associated with transmission performance ofthe UE. Note that the one or more metrics may include any of the metrics(and/or conditions) described above in reference to FIG. 10A.

Processor 1102 may also include monitor module 1131 configured todetermine that the UE needs to reduce transmissions per time period. Thedetermination may be based at least in part on at least one metric ofthe one or more metrics. In other words, the UE may determine that atleast one of the one or more metrics indicates that the UE needs toreduce transmissions per time period. Note that the one or more metricsmay include any of the metrics (and/or conditions) described above inreference to FIG. 10A. Additionally, the indication may be based oncomparison of a metric to an associated threshold as described above.

Processor 1102 may also include switch module 1141 configured to switchthe UE a second transmit duty cycle. The second transmit duty cyclespecifies a second number of transmissions per time period. The secondnumber may be less than the first number. The second transmit duty cyclemay correspond to state 1004 as described above with reference to FIG.10A.

Additionally, processor 1102 may include second operate module 1151configured to operate the UE according to the second transmit dutycycle.

It is apparent for those skilled in the art that, for the particularprocesses of the modules described above (such as modules 1111, 1121,1131, 1141, and 1151), reference may be made to the corresponding steps(such as steps 1110, 1120, 1130, 1140, and 1150, respectively) in therelated process embodiment sharing the same concept and the reference isregarded as the disclosure of the related modules as well. Furthermore,processor 1102 may be implemented in software, hardware or combinationthereof. More specifically, processor 1102 may be implemented as aprocessing element, which includes, for example, circuits such as anASIC (Application Specific Integrated Circuit), portions or circuits ofindividual processor cores, entire processor cores, individualprocessors, programmable hardware devices such as a field programmablegate array (FPGA), and/or larger portions of systems that includemultiple processors. Additionally, processor 1102 may be implemented asa general-purpose processor such as a CPU, and therefore each module canbe implemented with the CPU executing instructions stored in a memorywhich perform a respective step.

FIG. 12A shows a flow diagram illustration of a method 1200 forswitching between transmit duty cycles, according to some embodiments.The method shown in FIG. 12A may be used in conjunction with any of thecomputer systems, devices, elements, or components disclosed herein,among other devices. In various embodiments, some of the method elementsshown may be performed concurrently, in a different order than shown, ormay be omitted. Additional method elements may also be performed asdesired. As shown, the method 1200 may be performed as follows.

At 1210, the UE may operate in a first state associated with a firsttransmit duty cycle. The first state may correspond to state 1002 above.The first transmit duty cycle may specify a first number oftransmissions per time period.

At 1220, the UE may monitor a plurality of metrics associated withtransmission performance of the UE. Note that the plurality of metricsmay include any of the metrics (and/or conditions) described above inreference to FIG. 10A.

At 1230, the UE may determine that at least one metric of the pluralityof metrics indicates that the UE may need to reduce transmissions pertime period. The indication may be based on comparison of a metric to anassociated threshold as described above.

At 1240, the UE may switch to a second state. The second state may beassociated with a second transmit duty cycle. The second transmit dutycycle may specify a second number of transmissions per time period. Thesecond number may be less than the first number. The second state maycorrespond to state 1004 above. The switch may correspond to switchevent 1006 above.

In some embodiments, the UE may transmit an indication to a base stationthat the UE is switching to the second transmit duty cycle. Theindication may be included in a MAC control element.

In some embodiments, the UE may operate in the second state anddetermine that at least one of metric of the one or more metricsindicates that the UE can increase transmissions. The UE may switch,based on the determination that at least one of metric of the one ormore metrics indicates that the UE can increase transmissions, to thefirst state. The switch may correspond to switch event 1008 above.

FIG. 12B illustrates a processor including modules for switching betweentransmit duty cycles, according to some embodiments. In someembodiments, radio 1232 (which may be equivalent to radio 330 describedabove) may be coupled to processor 1202 (which may be equivalent toprocessor(s) 302 described above). The processor may be configured toperform the method described above in reference to FIG. 12A. In someembodiments, processor 1202 may include one or more modules, such asmodules 1211-1241, and the modules may be configured to perform varioussteps of the method described above in reference to FIG. 12A. As shown,the modules may be configured as follows.

In some embodiments, processor 1202 may include operate module 1211configured to operate the UE in a first state associated with a firsttransmit duty cycle. The first state may correspond to state 1002 above.The first transmit duty cycle may specify a first number oftransmissions per time period.

Processor 1202 may also include monitor module 1221 configured tomonitor a plurality of metrics associated with transmission performanceof the UE. Note that the plurality of metrics may include any of themetrics (and/or conditions) described above in reference to FIG. 10A.

In addition, processor 1202 may include determine module 1231 configuredto determine that at least one metric of the plurality of metricsindicates that the UE may need to reduce transmissions per time period.The indication may be based on comparison of a metric to an associatedthreshold as described above.

Additionally, processor 1202 may include switch module 1241 configuredto switch the UE to a second state. The second state may be associatedwith a second transmit duty cycle. The second transmit duty cycle mayspecify a second number of transmissions per time period. The secondnumber may be less than the first number. The second state maycorrespond to state 1004 above. The switch may correspond to switchevent 1006 above.

It is apparent for those skilled in the art that, for the particularprocesses of the modules described above (such as modules 1211, 1221,1231, and 1241), reference may be made to the corresponding steps (suchas steps 1210, 1220, 1230, and 1240, respectively) in the relatedprocess embodiment sharing the same concept and the reference isregarded as the disclosure of the related modules as well. Furthermore,processor 1202 may be implemented in software, hardware or combinationthereof. More specifically, processor 1202 may be implemented as aprocessing element, which includes, for example, circuits such as anASIC (Application Specific Integrated Circuit), portions or circuits ofindividual processor cores, entire processor cores, individualprocessors, programmable hardware devices such as a field programmablegate array (FPGA), and/or larger portions of systems that includemultiple processors. Additionally, processor 1202 may be implemented asa general-purpose processor such as a CPU, and therefore each module canbe implemented with the CPU executing instructions stored in a memorywhich perform a respective step.

FIG. 13A shows a flow diagram illustration of a method 1300 forswitching between transmit duty cycles, according to some embodiments.The method shown in FIG. 13A may be used in conjunction with any of thecomputer systems, devices, elements, or components disclosed herein,among other devices. In various embodiments, some of the method elementsshown may be performed concurrently, in a different order than shown, ormay be omitted. Additional method elements may also be performed asdesired. As shown, the method 1300 may be performed as follows.

At 1310, the UE may detect that it is transmitting according to a firsttransmit duty cycle. The first transmit duty cycle may specify a firstnumber of transmissions per time period. The first transmit duty cyclemay be associated with a first state, such as state 1002 above.

At 1320, the UE may determine an occurrence of at least one condition.The occurrence may indicate that the UE needs to reduce transmissionsper time period. In some embodiments, the occurrence may be based onmonitoring of metrics or conditions such as those described above inreference to FIG. 10A.

At 1330, the UE may switch to a second transmit duty cycle in responseto the determination. The second transmit duty cycle may specify asecond number of transmissions per time period and the second number isless than the first number. The second transmit duty cycle may beassociated with a second state. The second state may correspond to state1004 above. The switch may correspond to switch event 1006 above.

In some embodiments, the UE may detect that the UE is transmittingaccording to the second state and determine an occurrence of at leastone additional condition. The occurrence may indicate that the UE canincrease transmissions per time period and the UE may switch, based onthe determination of the occurrence of the at least one additionalcondition, to the first transmit duty cycle.

FIG. 13B illustrates a processor including modules for switching betweentransmit duty cycles, according to some embodiments. In someembodiments, radio 1332 (which may be equivalent to radio 330 describedabove) may be coupled to processor 1302 (which may be equivalent toprocessor(s) 302 described above). The processor may be configured toperform the method described above in reference to FIG. 13A. In someembodiments, processor 1302 may include one or more modules, such asmodules 1311-1331, and the modules may be configured to perform varioussteps of the method described above in reference to FIG. 13A. As shown,the modules may be configured as follows.

In some embodiments, processor 1302 may include detect module 1311configured to detect that the UE is transmitting according to a firsttransmit duty cycle. The first transmit duty cycle may specify a firstnumber of transmissions per time period. The first transmit duty cyclemay be associated with a first state, such as state 1002 above.

Additionally, processor 1302 may include determine module 1320configured to determine an occurrence of at least one condition. Theoccurrence may indicate that the UE needs to reduce transmissions pertime period. In some embodiments, the occurrence may be based onmonitoring of metrics or conditions such as those described above inreference to FIG. 10A.

In addition, processor 1302 may include switch module 1331 configured toswitch the UE to a second transmit duty cycle in response to thedetermination. The second transmit duty cycle may specify a secondnumber of transmissions per time period and the second number is lessthan the first number. The second transmit duty cycle may be associatedwith a second state. The second state may correspond to state 1004above. The switch may correspond to switch event 1006 above.

It is apparent for those skilled in the art that, for the particularprocesses of the modules described above (such as modules 1311, 1321,and 1331), reference may be made to the corresponding steps (such assteps 1310, 1320, and 1330, respectively) in the related processembodiment sharing the same concept and the reference is regarded as thedisclosure of the related modules as well. Furthermore, processor 1302may be implemented in software, hardware or combination thereof. Morespecifically, processor 1302 may be implemented as a processing element,which includes, for example, circuits such as an ASIC (ApplicationSpecific Integrated Circuit), portions or circuits of individualprocessor cores, entire processor cores, individual processors,programmable hardware devices such as a field programmable gate array(FPGA), and/or larger portions of systems that include multipleprocessors. Additionally, processor 1302 may be implemented as ageneral-purpose processor such as a CPU, and therefore each module canbe implemented with the CPU executing instructions stored in a memorywhich perform a respective step.

FIGS. 14A-14C—TDD UL/DL Frame Configurations

In current LTE 3GPP specifications (e.g., Rel-8 through Rel-12), 7 timedivision duplex (TDD) uplink/downlink (UL/DL) frame configurations aredefined. They are statically configured across all intra frequencycells. The LTE frame may have a periodicity of 5 or 10 milliseconds(ms). According to the specifications, all UEs use the same static TDDUL/DL configuration in a TDD cell. FIG. 14A illustrates the 7 TDD UL/DLframe configurations according to the specifications. As shown, eachframe includes 10 sub-frames (sfn0-sfn9), with each sub-frame designatedfor uplink (U or UL), downlink (D or DL), or special (S). Note that aspecial sub-frame is used to transition from a downlink sub-frame to anuplink sub-frame but not necessary when the UE transitions from anuplink sub-frame to a downlink sub-frame.

FIG. 14B illustrates acknowledge (ACK) and negative acknowledge (NAK)downlink association set index, K, as defined in the current LTE 3GPPspecifications association sets for each sub-frame of each TDD UL/DLframe, where K: {k0, k1, . . . km−1}. For example, for configuration 1which has a standard allocation of DSUUDDSUUD (see FIG. 14A), sub-frame2 has an allocation set of {6, 7}, sub-frame 3 has an allocation set of{4}, and so forth.

FIG. 14C illustrates adjustments to the downlink association set index,K, according to the current LTE 3GPP specifications. For example, asexplained in the current LTE 3GPP specifications, for TDD UL/DLconfigurations 1-6 and normal HARQ operation, the UE shall upondetection of a PDCCH with DCI format 0 and/or a PHICH transmission insub-frame n intended for the UE, adjust the corresponding PUSCHtransmission in sub-frame n+K, with K given in the table illustrated inFIG. 14C. As another example, for TDD UL/DL configuration 0 and normalHARQ operation the UE shall upon detection of a PDCCH with DCI format 0and/or a PHICH transmission in sub-frame n intended for the UE, adjustthe corresponding PUSCH transmission in sub-frame n+K if the MSB of theUL index in the DCI format 0 is set to 1 or PHICH is received insub-frame n=0 or 5, with K given in the table illustrated in FIG. 14C.As another example, if, for TDD UL/DL configuration 0 and normal HARQoperation, the LSB of the UL index in the DCI format 0 is set to 1 insub-frame n or a PHICH is received in sub-frame n=0 or 5 or PHICH isreceived in sub-frame n=1 or 6, the UE shall adjust the correspondingPUSCH transmission in sub-frame n+7. However If, for TDD UL/DLconfiguration 0, both the MSB and LSB of the UL index in the DCI format0 are set in sub-frame n, the UE shall adjust the corresponding PUSCHtransmission in both sub-frames n+k and n+7, with K given in the tableillustrated in FIG. 14C.

Dynamic UL Sub-Frame Allocation for TDD Low Power LTE

As mentioned above, in order to support LTE cellular technology in lowpower devices (e.g., UE's that are power limited and/or power restricteddue to battery size or batter charge, among other reasons), variousbasic issues should be considered. First, low power devices may havelimited RF range in both transmit (TX) and receive (RX). Additionally,low power devices may have both limited peak and average TX power for ULcommunications. Further, support for low power devices should becompatible with, or an extension of, current 3GPP LTE standards. Inaddition, support for low power devices should have minimum or no impacton LTE network capacity and LTE physical layers. In other words, supportfor low power devices should be devised as to ease implementation.

Thus, in some embodiments a low power device (e.g., UE 106 describedabove) may conserve battery drain with the implementation of a transmit(TX) duty cycle. In other words, to prevent quick battery current draindue to consecutive TX transmission in higher TX power conditions, a TXduty cycle may be used by the low power device. In such embodiments, thenumber of sub-frames in which the low power device may transmit may bereduced. Additionally, a number of TX sub-frames (e.g., UL sub-frames inwhich the low power device transmits) in a TX duty cycle period may berelated to the TX power of the TX sub-frames. For example, in a dutycycle period, only one or N (e.g., a number greater than 1, in otherwords, one or more) TX sub-frames may be transmitted in maximum TXpower. Further, the number of TX sub-frames (contiguous ornon-contiguous) in a duty cycle period may increase as the TX powerdecreases. In other words, as the power requirements for transmissiondecreases, the more times (e.g., more often) a low power device maytransmit in a duty cycle. Thus, a relationship between the number of TXsub-frames and corresponding TX power may be defined and quantified.Note that in some embodiments, under certain TX power thresholdconditions, contiguous TX in a duty cycle period may be allowed.Additionally, in some embodiments, the TX duty cycle period may beextended as needed; for example, due to heavy system usage or batterystate of charge (e.g., the batter power runs low). Note that since theTDD LTE UL/DL frame configuration has 5 ms or 10 ms periodicity, the TXduty cycle period should be chosen as a multiple of 10 milliseconds (ms)(e.g., N*10 ms). Further, as discussed in more detail below, for FDDLTE, due to both UL and DL hybrid automatic repeat request (HARD) roundtrip time (RTT) being 8 ms, the duty cycle should be chosen as amultiple of 8 ms (e.g., N*8 ms)

As mentioned above, LTE defines seven UL/DL frame configurations whichare statically configured across all intra frequency cells. Thus, the3GPP specifications (e.g., the LTE standards) do not have any mechanismfor the UE (e.g., the low power device) to inform the network (e.g.,base station 102) of how many TX (UL) sub-frames the UE may be capableof in a TX duty cycle period (e.g., 10 ms). Thus, there are threeconsequences that may occur due to the UE being unable to inform thenetwork of the UE's TX duty cycle. First, based on a UE pending databuffer status report, the network may assign UL grants in multiple UL TXsub-frames, however, the UE may not be able to transmit in each of thesub-frames assigned by the UL grants due to the TX duty cycle limitationand network radio resources may be wasted when the UE does not transmitin the all assigned UL sub-frames.

Second, since TDD LTE UL/DL frame configurations are asymmetric (each ULsub-frame may have more than one DL sub-frame associated with it fortransmission of corresponding ACK/NAKs), DL sub-frame association setsfor each UL sub-frame are statically defined per each UL/DL frameconfiguration as illustrated in FIG. 14B. However, since the UE may notbe able to transmit on all TX sub-frames defined in a static UL/DL frameconfiguration due to TX duty cycle limitation, the ACK/NAKs for DLsub-frames in a DL sub-frame association set for an un-transmitted UL TXsub-frame cannot be transmitted and the network may re-transmitcorresponding DL sub-frames. Eventually, this may lead to radio linkfailure.

Third, other layer one signals transmitted on UL PUCCH (such as periodicCQI and SRS) cannot be transmitted on assigned sub-frames due to the TXduty cycle. In other words, the UE was assigned an UL sub-frame and thenetwork expects to receive periodic CQI and SRS in that sub-frame, butdue to the TX duty cycle, the UE does not transmit in the assignedsub-frame. Such a condition may lead to the network determining toincrease BLER (block error rate) unnecessarily which may eventuallycause UL radio link failure. Therefore, improvements in the field aredesirable.

As described above in reference to FIG. 14A, there are seven static TDD(time division duplex) UL/DL sub-frame allocations (configurations 0-6).Thus, based on the static configuration of the cell, the low powerdevice (e.g., UE 106) may have up to six TX duty cycles, or power stages(or power states). For example, in some embodiments, as shown in FIG.15A, the low power device may have six different power stages (states)701-706 (e.g., may transmit between 1 and 6 times in a frame) for TDDUL/DL configuration 0 described above. The power stages may include asingle transmission per frame (701 a-b), two transmissions per frame(702), three transmissions per frame (703), four transmissions per frame(704), five transmissions per frame (705), or the prior art (e.g.,standards defined for TDD UL/DL configuration 0) six transmissions perframe (706). Note that when the power stage (or TX duty cycle) includesless than six transmissions in a frame (e.g., the standard allocation),the network may allocate which sub-frames the low power device transmitsin. For example, as shown at 701 a and 701 b, when the TX duty cycle is1 transmission out of 10 sub-frames (1/10), the low power device may beallocated any of sub-frames 2 (701 b), 3, 4 (701 a), 7, 8, or 9.Signaling methods between the network and the low power device may beused to determine which sub-frames will be allocated for instances whenthe TX duty cycle is less than the prior art static UL/DL sub-frameallocation are described below in detail.

In some embodiments, TX power may be calculated based on current pathloss, network minimum required PUCCH/PUSCH nominal power, and current ULpower control command which may be specified in 3GPP specifications.Additionally, when the TX power changes, the low power device may betriggered to enter a different TX power stage (or change TX duty cycle)with an associated maximum number of TX sub-frames. Thus, the low powerdevice may send information (e.g., maximum number of TX sub-frames in aframe) to the network (e.g., base station 102) via a MAC control elementwhich, in some embodiments, may be included on any UL MAC PDU. In otherwords, the low power device may request to transmit in less than thestatically configured number of sub-frames allocated by the network.

In response to receiving the information (e.g., the request from the lowpower device to transmit in less than the statically configured numberof sub-frames), the network (base station 102) may allocate sub-framesto the low power device based on the static TDD UL/DL configuration ofthe cell. For example, as discussed above and illustrated in FIG. 15A,the network may allocate sub-frames to the low power device based on theTX duty cycle (or TX power stage) of the low power device and the staticTDD UL/DL configuration for the cell. Thus, as shown at 702 of FIG. 15A,if the cell has configuration 0 and the low power device has a TX dutycycle of 2/10, the network may allocate sub-frames 2 and 3 to the lowpower device. Of course, since configuration 0 is defined to allocate 6sub-frames for TX (UL), the network may assign any combination of the 6sub-frames to the low power device based on the TX duty cycle. Thus,although sub-frames 2 and 3 are shown allocated, the network mayallocate any two of sub-frames 2, 3, 4, 7, 8, and 9 if the low powerdevice has a TX duty cycle of 2/10. FIGS. 15B-15D further illustratepossible configurations for various combinations of TX duty cycle of thelow power device and static TDD UL/DL configurations.

Note that in some embodiments, the network may send the allocation(e.g., information) based on the TDD UL/DL configuration of the cell andthe TX duty cycle of the low power device via a MAC control elementwhich may be included on any DL MAC PDU.

As noted above in reference to FIG. 14B, the PUCCH/PUSCH in an ULsub-frame may carry ACK/NAKs for multiple DL sub-frames which form theDL association set for each assigned UL sub-frame. However, when the lowpower device requests less than the standard allocated UL sub-frames(e.g., due to a TX duty cycle of less than the standard allocation), theDL association set for each allocated UL sub-frame may be different fromthe allocation set for each TDD UL/DL configuration defined in the 3GPPLTE specification. For example, if an UL sub-frame that would have beenallocated based on the defined static TDD UL/DL configuration but is notdue to the low power device's TX duty cycle, the unassigned ULsub-frame's downlink association set may be merged to the next closestallocated UL sub-frame's downlink association set. For example, if theTDD UL/DL configuration is configuration 0 (standard allocation of 6 ULsub-frames and 2 DL sub-frames as DSUUUDSUUU) and the low power devicehas a TX duty cycle of 4/10, then the network may allocate sub-frames 4,7, 8, and 9 and not allocate sub-frames 2 and 3 (modified allocation of4 UL sub-frames and 2 DL sub-frames as DSxxUDSUUU). Since sub-frames 2and 3 are not allocated, then sub-frame 2 and 3's downlink associationsets (6 for sub-frame 2, none for sub-frame 3) may be merged tosub-frame 4's, which becomes {6, 4}. As another example, if the staticTDD UL/DL configuration is configuration 1 (standard allocation of 4 ULsub-frames and 4 DL sub-frames as DSUUDDSUUD) and the low power devicehas a TX duty cycle of 3/10, then the network may allocate sub-frames 3,7, and 8 and not allocate sub-frame 2 (modified allocation of 3 ULsub-frames and 4 DL sub-frames as DSxUDDSUUD). Since sub-frame 2 is notallocated, then sub-frame 2's downlink association set {7, 6} may bemerged to sub-frame 3's, which becomes {7, 6, 4}.

In some embodiments, a downlink assignment index (DAI) in PDCCH DCIx andDCI0 (downlink control information formats) may be based on above mergeddownlink association set instead of as defined in the 3GPP standard.Thus, the DAI in DCI0 may represent the total number of DL sub-frames tobe ACK/NAK in a merged downlink association set and the DAI in DCIx mayrepresent the cumulative number of DL sub-frames to be ACK/NAK in themerged downlink association set.

Note that even though there are a maximum of 6 possible TX power stages(or TX duty cycles) for the low power device, the transitions betweendifferent power stages may not be necessary to trigger above mentionedmessage to network for a new UL sub-frame allocation. For example, insome embodiments, to avoid excessive messaging between the low powerdevice and the network, the low power device may remain with lesspossible number of TX sub-frames in an allocation with higher TX power.In other words, if the low power device originally requested anallocation based on a TX duty cycle of x/10, the low power device maynot request a new allocation based on a new duty cycle of y/10 (ygreater than x) to avoid excessive messaging.

In certain embodiments, the network may not change UL allocation to anumber of allocated TX sub-frames more than a previous allocationwithout the low power device's request. However, the network may changeUL allocation with less or equal number of allocated TX sub-frames thana previous allocation without the low power device's request. In otherwords, if the low power device has a TX duty cycle of x/10, the networkmay vary the allocation so long as the low power device is not requiredto transmit more than x/10 sub-frames. This may allow the networkscheduler to move the low power device's allocation within the frame tooptimize available UL sub-frames for other UEs. Additionally, thenetwork scheduler may downgrade the allocation due to detected higher ULBLER or other channel condition measures.

Dynamic Switch Between UL Sub-Frame Allocations in TDD-LTE

As mentioned above (and illustrated in FIG. 14A), there are 7 TDD staticUL/DL frame configurations which are statically configured across allintra frequency cells. Additionally, based on the statically configuredTDD UL/DL frame configuration and the low power device's requested TXduty cycle (number of TX sub-frames in a frame), each TDD UL/DLconfiguration may have multiple possible UL sub-frame allocations. Forexample, TDD UL/DL configuration 1 (standard allocation of 4 ULsub-frames and 4 DL sub-frames as DSUUDDSUUD) has 4 available ULsub-frame allocations for a TX duty cycle of 1/10 (DSUxDDSxxD,DSxUDDSxxD, DSxxDDSUxD, and DSxxDDSxUD). In other words, since TDD UL/DLconfiguration 1 is defined to have 4 UL sub-frames, the network mayassign any of the 4 available UL sub-frames to a low power devicerequesting 1 UL sub-frame per frame. Further, if the TX duty cycle is2/10, there are 6 available UL sub-frame allocations (DSUUDDSxxD,DSUxDDSUxD, DSUxDDSxUD, DSxUDDSUxD, DSxUDDSxUD, and DSxxDDSUUD). Thus,in addition to the above described low power device request forsub-frame allocation base on TX duty cycle, improvements in signaling toallow for dynamic switching between UL sub-frame allocations based oncurrent UL/DL configuration and TX duty cycle is desirable.

Thus, in some embodiments, the low power device (e.g., UE 106) mayinform the network (e.g., base station 102) of its currently supportedTX duty cycle (e.g., the number of UL sub-frames the low power device iscurrently capable of transmitting in a frame) via a MAC control elementas described above. In addition, the MAC control element may be 8 bitslong to indicate the number of requested UL sub-frames in a frame andthe UL sub-frame allocation from the TDD UL/DL static configuration maybe considered the initial UL sub-frame configuration. Thus, any furtherUL sub-frame allocation or de-allocation from the network (e.g., inresponse to the low power device's request) may be an update to theinitial (or existing) UL sub-frame allocation. For example, a new ULsub-frame allocation may add several UL sub-frames in a frame as newlyallocated and delete several UL sub-frames in a frame as newlyde-allocated.

In some embodiments, to update an UL sub-frame as newly de-allocated(e.g., deleted or removed), the network may use a DCI0 format in a DLPDCCH sub-frame. Note that DCI0 format may be normally used for thescheduling of corresponding UL PUSCH sub-frames. In such embodiments,the DCI0 format may be used to also indicate if the corresponding ULsub-frame is de-allocated. Further, if the MAC PDU transmitted in aprevious hybrid automatic repeat request (HARQ) transmission cycle isacknowledged, then 2 bits are used: 1 bit for a de-allocation indictorand 1 bit for the ACK/NAK. Note that DCI0 includes the followinginformation:

-   -   1. Flag for format0/format1A differentiation (1 bit).    -   2. Frequency hopping fag (1 bit).    -   3. Resource block assignment and hopping resource allocation        ([log(N*(N+1)/2] bits).    -   4. Modulation and coding scheme and redundancy version (5 bits).    -   5. New data indicator (1 bit).    -   6. TPC command for scheduled PUSCH (2 bits).    -   7. Cyclic shift for DM RS (3 bits).    -   8. UL index (2 bits).    -   9. Downlink Assignment Index (2 bits).    -   10. CQI request (1 bit).

In some embodiments, the 2 bits for the de-allocation indicator and theACK/NAK may be re-used from the bits from #2, #3, #4, #5, #6 and #7 ofDCI0.

Note that after the PDCCH sub-frame with the specific DCI0 format (e.g.,indicating the de-allocation of the UL sub-frame) is sent to the lowpower device, the network may expect an ACK from the low power device onthe corresponding UL sub-frame for the sent DCI0 on the PUCCH. Inaddition, when the DCI0 format specifies the de-allocation of the ULsub-frame, the ACK/NAKs for the DL sub-frames in the to be de-allocatedUL sub-frame's DL association set may be received by the network (andsent by the low power device) on the next closest active UL sub-frame asdescribed above. In addition, once the network receives the ACK from thelow power device on the corresponding UL sub-frame for the sent DCI0 onthe PUCCH, the network may determine that allocation (e.g., thede-allocation of the UL sub-frame) is complete and further determinethat the de-allocated UL sub-frame's downlink association set has beenmerged to next closest active UL sub-frame's downlink association set bythe low power device. Note that the HARQ process associated with thede-allocated UL sub-frame may also be disabled. However, if no ACK isdetected, the network may determine that the allocation (e.g., thede-allocation of the UL sub-frame) has not been completed and maytransmit the specific DCI0 format on the same PDCCH sub-frame in a nextallocation period (e.g., same sub-frame on next frame).

Additionally, to add an UL sub-frame in a frame as newly allocated, thenetwork may also use a DCI0 format in a DL PDCCH sub-frame whichnormally is used for the scheduling of corresponding UL PUSCH sub-frameto implicitly indicate the corresponding UL sub-frame is allocated forfurther UL transmission which includes both PUSCH and PUCCH. Note that,if there is no PUSCH scheduling (e.g., only UL sub-frame allocation),the above DCI0 format's bits from #2, 3, 4, 5, 6, and 7 may be re-usedfor a one bit indicator of the UL sub-frame allocation. Note furtherthat if a normal DCI0 in PDCCH is sent to the low power device for theto be allocated UL sub-frame and the network receives (and the low powerdevice sends) PUSCH on the corresponding UL sub-frame, the network maydetermine that the adding of the UL sub-frame to the existing ULsub-frame allocation has been completed. Also, if the network receives(and the low power device sends) PUCCH with an ACK on the correspondingUL sub-frame, the network may determine that the adding of the ULsub-frame to the existing UL sub-frame allocation has been completed.

Once the allocation of the UL sub-frame has been completed (e.g., thenewly added allocation has been added to the existing UL sub-frameallocation), then the newly allocated UL sub-frame's downlinkassociation set may be established by the low power device. Thus, thecontent of the newly allocated UL sub-frame's downlink association setmay be removed from the next closest allocated UL sub-frame's downlinkassociation set and the network may establish a HARQ process associatedwith the newly allocated UL sub-frame.

Note that if neither the PUSCH nor the ACK on the PUCCH has beenreceived by the network (or sent by the low power device) on the to beallocated UL sub-frame, then the network may repeat the above describedprocedure for adding the UL sub-frame in a frame as newly allocated inthe next allocation period (e.g., the next frame).

Further, when the low power device receives the DCI0 format in the PDCCHsub-frame as described above, it may take the following actions:

If the DCI0 format indicates that the corresponding UL sub-frame is tobe de-allocated, the low power device may disable the HARQ processcorresponding to the to be de-allocated UL sub-frame. Additionally, ifthe specific DCI0 format indicates that the corresponding HARQ processis acknowledged, then the low power device may mark the correspondingradio link control (RLC) PDUs in the acknowledged MAC PDU asacknowledged. If the specific DCI0 format indicates that thecorresponding HARQ process is not acknowledged, then the low powerdevice may mark the corresponding RLC PDUs in the not acknowledged MACPUD as not acknowledged and may further schedule them to be transmittedusing other active UL HARQ processes. Additionally, the low power devicemay transmit an ACK for the received PDCCH sub-frame with the DCI0format on the corresponding to be de-allocated UL sub-frame in order toinform the network that the removing of the to be de-allocated ULsub-frame has been completed. Note that the received PDCCH sub-frame maybe part of the to be de-allocated UL sub-frame's downlink associationset, of which all downlink PDSCH sub-frames received may be ACK/NAK inthe next closest allocated UL sub-frame, along with all DL PDSCHsub-frames received in the downlink association set of the next closestallocated UL sub-frame.

If the DCI0 format indicates that the corresponding UL sub-frame is tobe allocated (added, re-allocated, or newly allocated), then the lowpower device may associate an un-used (disabled) UL HARQ process withthe to be allocated UL sub-frame and add it to the current set of activeUL HARQ processes. Additionally, if it is a standard DCI0 format, thenPUSCH with UL data may be sent by the low power device to the network(e.g., base station 102) on the to be allocated (e.g., newly activated)UL sub-frame which may implicitly indicate the procedure of allocatingthe to be allocated UL sub-frame into the existing sub-frame allocationhas been completed. Otherwise, if it is a specific DCI0 format, thenPUCCH with ACK may be sent by the low power device to the network (basestation 102) on the to be allocated (e.g., newly activated) UL sub-frameto complete the procedure of adding the to be allocated UL sub-frameinto the existing sub-frame allocation. Further, the low power devicemay establish a DL association set for the to be allocated (newlyactivated) UL sub-frame and remove any DL sub-frames included in theestablished DL association set from the next closest allocated ULsub-frame's DL association set.

UL/DL Sub-Frame Allocation in FDD Low Power LTE

Similar to the issues described above with respect to TDD, there areissues with respect to a low power device using a TX duty cycle asdescribed above for frequency division duplex (FDD) LTE. First, asdefined in the current LTE 3GPP specification (e.g., Rel-8 throughRel-12), FDD LTE UL and DL HARQ have a round trip time (RTT) of 8 ms.Thus, the use of a TX duty cycle as described above may violate thistimeline. Additionally, the current LTE 3GPP specifications for FDD LTEdo not define a mechanism for the low power device (e.g., UE 106) toinform the network (e.g., base station 102) of how many TX sub-framesthe low power device may be capable of in a duty cycle period (e.g., howmany sub-frames the low power device may be able to transmit in duringan 8 ms RTT). There may be three consequences to not having such amechanism: (1) based on the low power device's pending data bufferstatus report, the network may assign UL grants in multiple UL TXsub-frames, but the low power device may not be able to transmit in allUL sub-frames granted (allocated by the network) due to the TX dutycycle limitation which may lead to wasted network radio resources; (2)in FDD LTE, for any DL PUSCH sub-frame, the low power device musttransmit its ACK/NAK on UL PUCCH/PUSCH sub-frame 4 ms later, however,since the low power device may not be able to transmit on all TXsub-frames allocated by the network due to the TX duty cycle limitation,the ACK/NAKs for received DL sub-frames on an un-transmitted UL TXsub-frame may not be transmitted which may cause the network tore-transmit corresponding DL sub-frames which may result in radio linkfailure; (3) other layer one signals transmitted on UL PUCCH such asperiodic CQI and SRS may not be transmitted on untransmitted UL TXsub-frames due to the TX duty cycle limitation which could falsely leadthe network to increase BLER and may also result in UL radio linkfailure. Therefore, improvements are desirable.

In LTE FDD, there are 8 UL sub-frames in an allocation period, thus,there are eight possible TX power stages, each associated with a numberof TX sub-frames the low power device may be capable of transmitting inthe 8 ms allocation period based on currently required TX power. Thecurrently required TX power may be calculated based on current pathloss, network minimum required PUCCH/PUSCH nominal power, and current ULpower control command (specified in current LTE 3GPP specifications).Note that changing currently required TX power may trigger the low powerdevice to enter a different TX power stage with an associated maximumnumber of TX sub-frames. Thus, in some embodiments, the low power devicemay send this information (number of capable TX sub-frames in anallocation period) to the network via a MAC control element. The MACcontrol element may be piggybacked on any UL MAC PDU.

Similar to the TDD scenario described above, the network may receive themaximum number of TX sub-frames request from the low power device. Insome embodiments, the network may restrict UL sub-frames allocated tothe low power device based on the request. The network may have fouroptions for the UL sub-frame allocation restrictions. First, in someembodiments, if the low power device has indicated to the network (e.g.,via an LTE capability indication message) that the low power devicesupports half-duplex for the band the low power device has camped on,then out of the 8 sub-frames in the allocation period, N may be for ULand 8-N may be for DL. In such instances (e.g., half-duplex mode),sub-frame allocation may be performed dynamically by the network (e.g.,base station 102) via the network scheduler as mentioned in LTE 3GPPRel-8 half-duplex LTE.

In such embodiments, the low power device may be able to transmit at anytime per network schedule. Thus, the low power device, based on thenetwork schedule, may be required to transmit UL PUSCH sub-frame basedon DCI0 UL grant received in a DL PDCCH sub-frame 4 ms earlier andtransmit DL ACK/NAK on a UL PDCCH/PUSCH sub-frame for a PDSCH sub-framereceived 4 ms earlier. Note that the low power device may receive DLsub-frames unless doing transmission.

Alternatively, the allocation may be performed semi-statically by thenetwork scheduler by assigning sub-frame allocations to the low powerdevice via a sub-frame allocation configuration message in response toreceiving the maximum number of TX sub-frames request from the low powerdevice. The network may send the sub-frame allocation information to thelow power device via a MAC control element which may be piggybacked onany DL MAC PDU.

Second, in some embodiments, if the low power device supports fullduplex on the band it is camped on, then there are 8 DL sub-frames forDL reception in the allocation period and N UL sub-frames out of 8 maybe assigned by the network for UL transmission. In some embodiments, thenetwork (e.g., base station 102) may assign a sub-frame allocation tothe low power device via a sub-frame allocation configuration message inresponse to receiving the maximum number of TX sub-frames request fromlow power device. The network may send the sub-frame allocationconfiguration message to the low power device via a MAC control elementwhich, similar to the above, may be piggybacked on any DL MAC PDU.

Third, in some embodiments, whether the low power device supports onlyhalf duplex or both full and half duplex on the band it is camped on,control signaling may be used by the network to assign a sub-frameallocation to the low power device. Thus, in some embodiments,PUCCH/PUSCH in a UL sub-frame may carry ACK/NAKs for multiple DLsub-frames which form a DL association set for each assigned ULsub-frame. Note that as defined in the LTE 3GPP specifications, withoutany UL restriction, each UL sub-frame's DL association set includes oneDL sub-frame which is received at sub-frame (n−4), where n is the ULsub-frame. Thus, if an UL sub-frame is not allocated, the unallocated ULsub-frame's downlink association set may be merged to a next closestallocated UL sub-frame's downlink association set. In other words,similar to TDD, the ACK/NACKs for multiple DL sub-frames are sent by thelow power device in the allocated sub-frame. Hence, a downlinkassignment index (DAI) may be introduced to FDD PDCCH DCIx and DCI0 fromTDD, and may be based on above described merged downlink associationset.

Fourth, in some embodiments, full duplex UEs (including low powerdevices) and half duplex UEs (including low power devices) may co-existin a FDD cell. A time for downlink-to-uplink switch may be created atthe low power device (e.g., UE 106) by ignoring the last OFDM symbol(s)in a sub-frame immediately preceding an UL sub-frame. Additionally, atime for uplink-to-downlink switch may be created by a timing advancesuch as (Nta+Nta_offset)Ts seconds, where Nta_offset=624Ts=20 us.

In some embodiments, a default dynamic symmetric UL/DL sub-frameallocation may be created as part of the network schedule (e.g., via thescheduler of base station 102). Examples of such FDD symmetric UL/DLsub-frame allocations are illustrated in FIG. 16A. In such embodiments,control signaling (transmission and ACK/NACK of transmission) betweenthe low power device and the network may be performed at fixed timeintervals (e.g., such as 4 ms). Additionally, a change in the low powerdevice's TX duty cycle configuration may be triggered by a low powerdevice event (e.g., an increase or decrease in required TX power) andthe low power device may send an UL MAC control element embedded in anyUL MAC PDU indicating a new number of sub-frames the low power devicemay be currently capable of transmitting in an allocation period. Notethat since the FDD UL/DL allocation is symmetric, a TX duty cycle of 1/8means that the low power device may only transmit in 1 UL and receive in1 DL sub-frame. Thus, such a configuration may not be able to utilizeall available radio resources in DL heavy use cases and UL heavy usecases.

In other embodiments, a semi-static, non-symmetric FDD UL/DL sub-frameallocation scheme may be utilized as illustrated in FIG. 16B. Similar tothe symmetric FDD UL/DL allocation, a change in the low power device'sTX duty cycle configuration may be triggered by a low power device event(e.g., an increase or decrease in required TX power) and the low powerdevice may send an UL MAC control element embedded in any UL MAC PDUindicating a new number of sub-frames the low power device may becurrently capable of transmitting in an allocation period. In suchembodiments, the number of DL to UL switches may be minimized and theremay not be a need to have fixed DL sub-frames 0 and 5 for all UEs(including the low power device). Further, the control signaling may besimilar to the control signaling method described above in reference toTDD. Thus, PUCCH/PUSCH in an UL sub-frame may include ACK/NAKs formultiple DL sub-frames. Additionally, there may be multiple ACK/NAKfeedback modes: bundling and multiplexing. Further, PHICHs in DLsub-frames may carry ACK/NACKs for multiple UL sub-frames as illustratedin FIG. 16C. Thus, DCI fields in PDCCH may be related to the FDD UL/DLallocation. An UL index may include at least two bits for specifying ULUL/DL timing relationships for power control, CQI reporting, and HARQtransmissions. A downlink assignment index (DAI) may include at leasttwo bits and may include information such as a number of PDSCHs in adownlink association set and may allow the low power device to detectmissing PDSCH and PDCCH sub-frames. FIG. 16D illustrates therelationship between UL and DL sub-frames for receiving ACK/NAKs and ULgrants on DL for UL PUSCH.

Note that DAI in DCI0 may represent the total number of DL sub-frames tobe ACK/NAK in the merged downlink association set. In addition, notethat DAI in DCIx may represent the cumulative number of DL sub-frames tobe ACK/NAK in a merged downlink association set.

Note that in some embodiments, the low power devices transition betweendifferent power stages may not always trigger the low power device tosend a message to the network for a new UL sub-frame allocation. Thus,in order to avoid excessive messaging between the low power device andthe network, the low power device may stay with less than the maximumpossible number of TX sub-frames in an allocation with higher TX power.Additionally, the network may not change the UL allocation to anallocation greater than a current (e.g., previous) allocation unless thelow power device requests a new allocation with a greater number of TXsub-frames. However, the network may change the UL allocation to anallocation with less TX sub-frames than a previous (e.g., current)allocation without the low power device requesting a new allocation witha lesser number of TX sub-frames. Thus, for example, if the networkscheduler determines that the low power device's allocation should bechanged (either keeping the same number or UL sub-frames and changingwhich frames the low power device may use or reducing the number of ULsub-frames allocated to the low power device) in order to better use(e.g., optimize) network resources, then the allocation may be changedwithout the request of the low power device. Additionally, the networkmay downgrade (e.g., reduce the number of UL sub-frames allocated to thelow power device) if the network detects an change in BLER or otherchannel quality indicator that may indicate deteriorating channelconditions that may result in increased TX power for successfultransmission.

Further Embodiments

In some embodiments, a user equipment device (UE) may be configured tocommunicate with one or more base stations using radio frames thatinclude multiple sub-frames, transmit information regarding allocationof a portion of the sub-frames of a respective radio frame for each of aplurality of the radio frames for the UE, and transmit and receive datausing allocated sub-frames and not using unallocated sub-frames, whereinthe allocated sub-frames comprise portions of the sub-frames for each ofthe plurality of the radio frames, wherein the portions are less thanall of the sub-frames of each respective radio frame. The unallocatedsub-frames of one or more of the plurality of the radio frames may beallocated to another UE. The information may indicate a set of rules forallocating sub-frames to the UE and set of rules may be based ondetection of a low power condition or a poor radio condition.

The UE may also be configured to both transmit and receive data duringthe allocated sub-frames. The allocation may specify one or moresub-frames for receiving only and one or more sub-frames fortransmitting only.

The UE may also be configured to send and receive hybrid automaticrepeat request indications using the allocated sub-frames. The requestmay be included in a radio resource control (RRC) message and/or a mediaaccess control (MAC) protocol data unit (PDU) control element.

The UE may also be configured to request unlimited sub-frame allocationin response to a change in operating conditions.

In some embodiments, a method for providing improved communicationperformance in a cellular communication system may include a UEcommunicating with one or more base stations using radio frames thatinclude multiple sub-frames, requesting allocation of a portion of thesub-frames of a respective radio frame for each of a plurality of theradio frames for the UE, and transmitting and receiving data usingallocated sub-frames and not using unallocated sub-frames. The allocatedsub-frames may include a portion of the sub-frames that is less than allof the sub-frames for each of the plurality of the radio frames. Therequesting may be performed in response to an operating condition andmay include information associated with the operating condition.Alternatively, or in addition, the requesting may be performed using atleast one of a radio resource control (RRC) message and a media accesscontrol (MAC) protocol data unit (PDU) control element. The method mayalso include sending and receiving hybrid automatic repeat requestindications using the allocated sub-frames.

The method may include a second UE communicating with the one or morebase, requesting allocation of a second portion of the sub-frames of arespective radio frame for each of the plurality of the radio frames forthe second UE, and transmitting and receiving data using sub-framesallocated to the second UE and not using sub-frames allocated to the UE.In such embodiments, the requests by the first and second UEs requestingmay not specify particular sub-frames of the respective radio frame.

In some embodiments, a base station may be configured to receive, from aUE, a request for allocation of a portion of sub-frames for a respectiveradio frame of each of a plurality of radio frames, select sub-framesfor the respective radio frame and allocate the selected sub-frames tothe UE, wherein the allocated sub-frames make up a portion that is lessthan all of the sub-frames of the respective radio frame, and transmitdata to the UE and receive data from the UE using the allocatedsub-frames and not using unallocated sub-frames. The base station mayalso be configured to select the sub-frames of the respective radioframes to allocate to the UE based on sub-frame allocations for one ormore other UEs and/or allocate different sub-frames of the respectiveradio frame to multiple different UEs. The base station may beconfigured to indicate the allocated sub-frames using at least one of aradio resource control (RRC) message and a media access control (MAC)protocol data unit (PDU) control element. Additionally, the base stationmay be configured to select the sub-frames based on a set of rulesreceived from the UE, wherein the set of rules is based on powerlimitations of the UE.

In some embodiments, a UE may be configured to transmit firstinformation comprising a number of uplink (UL) sub-frames to betransmitted in a frame and receive, from a base station, a firstsub-frame allocation based on at least the first information. The ULsub-frames may be contiguous UL sub-frames. The first information mayfurther comprise a number of downlink (DL) sub-frames to be received ina frame and the DL sub-frames may be contiguous DL sub-frames. The firstinformation may also comprise a minimum number of sub-frames betweentransmit and receive. Additionally, the first information may begenerated based on power limitations of the UE. The first informationmay be indicated in a field of a radio resource control (RRC) connectionsetup message. In addition, the first information may be stored in thebase station. The UE may be configured according to the sub-frameallocation.

Further, the UE may be further configured to transmit second informationindicating that the UE can transmit in all UL sub-frames and receive inall DL sub-frames and receive, from the base station, a second sub-frameallocation based on at least the second information. The secondinformation may be transmitted by the UE when the UE is not powerlimited. The second information may be indicated in a field of a radioresource control (RRC) connection setup message. The first informationand the second information may be stored in the base station.

In addition, the UE may be further configured to transmit thirdinformation indicating that the UE can transmit in only half duplex forfrequency division duplexing (FDD).

In some embodiments, a UE may be configured to transmit firstinformation to a base station indicating that the UE is in a first powerstate, receive, from the base station, a first sub-frame allocationbased on at least the first information, and operate according to thefirst sub-frame allocation after receiving the first sub-frameallocation. The first power state may be one of power limited or notpower limited.

The UE may be further configured to transmit second information to thebase station indicating that the UE is in a second power state, whereinthe second power state is different from the first power state, receive,from the base station, a second sub-frame allocation based on at leastthe second information, wherein the second sub-frame allocation isdifferent than the first sub-frame allocation, and operate according tothe second sub-frame allocation after receiving the second sub-frameallocation. The first power state may be a power limited state and thesecond power state is a not power limited state. Alternatively, thefirst power state may be a not power limited state and the second powerstate is a power limited state. When the first power state is a powerlimited state, the first information may comprise one or more of: 1) anumber of contiguous uplink (UL) sub-frames to be transmitted in aframe; 2) a number of contiguous downlink (DL) sub-frames to be receivedin a frame; or 3) a minimum number of sub-frames between transmit andreceive. When the first power state is a power limited state, the firstinformation may comprise two or more of: 1) a number of contiguousuplink (UL) sub-frames to be transmitted in a frame; 2) a number ofcontiguous downlink (DL) sub-frames to be received in a frame; or 3) aminimum number of sub-frames between transmit and receive.

In some embodiments, a UE may be configured to transmit firstinformation to a base station indicating that the UE is in a powerlimited state, receive, from the base station, a first sub-frameallocation based on at least the first information, operate according tothe first sub-frame allocation after receiving the first sub-frameallocation, transmit second information indicating that the UE is not inthe power limited state, receive, from the base station, a secondsub-frame allocation based on at least the second information, andoperate according to the second sub-frame allocation after receiving thesecond sub-frame allocation. The UE may be further configured totransmit the second information, receive the second sub-frameallocation, and operate according to the second sub-frame allocationbefore transmitting the first information, receiving the first sub-frameallocation, and operating according to the first sub-frame allocation.In addition, the UE may be further configured to transmit the secondinformation in a sub-frame that is not allocated to the UE. The secondinformation may be transmitted in one of a schedule request (SR) signalor a radio resource control (RRC) message. Alternatively, or inaddition, the second information may be transmitted in a medium accesscontrol (MAC) control element as part of a UL MAC packet data unit(PDU). The UE may also be configured to determine that one or more of 1)a current power is below a power threshold or 2) current radioconditions are below a radio condition threshold, wherein the UE maytransmit the first information in response to determining that one ormore of 1) the current power is below the power threshold or 2) currentradio conditions are below a radio condition threshold.

In some embodiments, a base station may be configured to receive firstinformation from a user equipment device (UE) indicating that the UE isnot in a power limited state, send a first sub-frame allocation based onat least the first information, operate according to the first sub-frameallocation after send the first sub-frame allocation, determine that theUE has not transmitted for a specified number of contiguous sub-frames,send a second sub-frame allocation based on at least the secondinformation, and operate according to the second sub-frame allocationafter sending the second sub-frame allocation. The second sub-frameallocation may comprise one or more of: 1) a number of contiguous uplink(UL) sub-frames to be transmitted in a frame; 2) a number of contiguousdownlink (DL) sub-frames to be received in a frame; or 3) a minimumnumber of sub-frames between transmit and receive.

In some embodiments, a base station may be configured to receive, from auser equipment device (UE), first information comprising a number ofuplink (UL) sub-frames to be transmitted in a frame and transmit a firstsub-frame allocation based on at least the first information. The firstinformation comprises one or more of: 1) a number of contiguous uplink(UL) sub-frames to be transmitted in a frame; 2) a number of contiguousdownlink (DL) sub-frames to be received in a frame; or 3) a minimumnumber of sub-frames between transmit and receive and the firstsub-frame allocation may comprise one or more of: 1) the number ofcontiguous uplink (UL) sub-frames to be transmitted in a frame; 2) thenumber of contiguous downlink (DL) sub-frames to be received in a frame;or 3) the minimum number of sub-frames between transmit and receive.

In some embodiments, a UE may be configured to transmit firstinformation comprising one or more of: 1) a number of contiguous uplink(UL) sub-frames to be transmitted in a frame; 2) a number of contiguousdownlink (DL) sub-frames to be received in a frame; or 3) a minimumnumber of sub-frames between transmit and receive, from a base station,a first sub-frame allocation based on at least the first information.

In some embodiments, a UE may be configured to transmit firstinformation to a base station indicating that the UE is not in a powerlimited state, receive, from the base station, a first sub-frameallocation based on at least the first information, operate according tothe first sub-frame allocation after receiving the first sub-frameallocation, and when the UE enters a power limited state, discontinuetransmissions to the base station for a number of contiguous sub-frames,receive, from the base station, a second sub-frame allocation based onat least the UE entering the power limited state, and operate accordingto the second sub-frame allocation after receiving the second sub-frameallocation.

In some embodiments, a method for providing improved communicationperformance in a cellular communication system may include a UEperforming transmitting, to a base station, first information comprisinga number of uplink (UL) sub-frames to be transmitted in a frame andreceiving, from the base station, a first sub-frame allocation based onat least the first information. The first information comprises one ormore of: 1) a number of uplink (UL) sub-frames to be transmitted in aframe; 2) a number of continuous downlink (DL) sub-frames to be receivedin a frame; or 3) a minimum number of sub-frames between transmit andreceive.

In some embodiments, a method for providing improved communicationperformance in a cellular communication system may include a UEperforming transmitting first information to a base station indicatingthat the UE is in a power limited state, receiving, from the basestation, a first sub-frame allocation based on at least the firstinformation, operating according to the first sub-frame allocation afterreceiving the first sub-frame allocation, transmitting secondinformation indicating that the UE is not in the power limited state,receiving, from the base station, a second sub-frame allocation based onat least the second information, and operating according to the secondsub-frame allocation after receiving the second sub-frame allocation.

In some embodiments, a method for providing improved communicationperformance in a cellular communication system may include a UEperforming transmitting first information to a base station indicatingthat the UE is not in a power limited state, receiving, from the basestation, a first sub-frame allocation based on at least the firstinformation, operating according to the first sub-frame allocation afterreceiving the first sub-frame allocation, transmitting secondinformation indicating that the UE is in the power limited state,receiving, from the base station, a second sub-frame allocation based onat least the second information, and operating according to the secondsub-frame allocation after receiving the second sub-frame allocation.

Embodiments of the present disclosure may be realized in any of variousforms. For example some embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Still other embodimentsmay be realized using one or more programmable hardware elements such asFPGAs.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of a methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE 106) may be configured toinclude a processing element (or a set of processing elements) or aprocessor (or a set of processors) and a memory medium, where the memorymedium stores program instructions, where the processor (or processingelement) is configured to read and execute the program instructions fromthe memory medium, where the program instructions are executable toimplement a method, e.g., any of the various method embodimentsdescribed herein (or, any combination of the method embodimentsdescribed herein, or, any subset of any of the method embodimentsdescribed herein, or, any combination of such subsets). The device maybe realized in any of various forms.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A user equipment device (UE), comprising: atleast one antenna; at least one radio, wherein the at least one radio isconfigured to perform cellular communication using at least one radioaccess technology (RAT); one or more processing elements coupled to theat least one radio, wherein the one or more processing elements and theat least one radio are configured to perform voice and/or datacommunications; wherein the one or more processing elements and the atleast one radio are configured to cause the UE to: determine a powerlimitation at the UE; at a first time, in response to determining thepower limitation at the UE, transmit a first indication to a basestation indicating the power limitation at the UE via a first randomaccess channel (RACH) preamble to request a configuration of a limitedsub-frame allocation comprising a limited number of downlink and uplinksub-frames, wherein the first indication is indicated by a selection ofa first RACH preamble and/or a first RACH sub-frame location; performtransmit and receive operations during sub-frames of the limitedsub-frame configuration; at a second time, transmit a second indicationto the base station via a second RACH to request a configuration of afull sub-frame allocation comprising a frequency division duplex (FDD)sub-frame configuration without a half duplex FDD limitation, whereinthe second indication is indicated by selection of a second RACHpreamble and/or a second RACH sub-frame location; and perform transmitand receive operations during any of the FDD sub-frames.
 2. The UE ofclaim 1, wherein the UE co-exists in a cell served by the base stationwith at least one other UE, wherein the at least one other UE does nothave a power limitation and is configured to communicate according to anunlimited sub-frame configuration and full duplex frequency divisionduplex (FD-FDD).
 3. The UE of claim 1, wherein the power limitationresults in a limited radio frequency (RF) range for the UE.
 4. The UE ofclaim 1, wherein the power limitation at the UE is associated with oneor more of: battery charge state of the UE; or thermal conditions at theUE.
 5. The UE of claim 1, wherein the one or more processing elementsand the at least one radio are further configured to cause the UE to:transmit, within a subframe allocation based on a RACH configurationused by the UE for random access, at least a msg3 of a RACH procedureassociated with the indication transmitted via the RACH.
 6. The UE ofclaim 1, wherein, to determine the power limitation at the UE the one ormore processing elements and the at least one radio are furtherconfigured to cause the UE to: monitor one or more metrics associatedwith transmission performance of the UE; and determine that at least onemetric indicates that the UE needs to reduce transmissions.
 7. The UE ofclaim 6, wherein, to determine that the at least one metric indicatedthat the UE needs to reduce transmissions, the one or more processingelements and the at least one radio are further configured to cause theUE to: compare the at least one metric to a threshold associated withthe at least one metric; wherein said determining that at least onemetric of the one or more metrics indicates that the UE needs to reducetransmissions is based on said comparing.
 8. The UE of claim 6, whereinthe one or more metrics comprise one or more of: transmission blankingrate; audio frame error rate; chemical charge level of a battery of theUE; chemical charge dissipation rate of the battery of the UE; andthermal load on the UE.
 9. The UE of claim 1, wherein the UE is awearable device.
 10. An apparatus, comprising: a memory; and one or moreprocessors in communication with the memory, wherein the one or moreprocessors are configured to: determine a power limitation associatedwith the apparatus; at a first time, in response to determining thepower limitation, generate instructions to transmit an indication to abase station indicating the power limitation via a first random accesschannel (RACH) preamble to request a configuration of a limitedsub-frame allocation comprising a limited number of downlink and uplinksub-frames, wherein the first indication is indicated by a selection ofa first RACH preamble and/or a first RACH sub-frame location; generateinstructions to perform transmit and receive operations duringsub-frames of the limited sub-frame configuration; at a second time,generate instructions to transmit a second indication to the basestation via a second RACH to request a configuration of a full sub-frameallocation comprising a frequency division duplex (FDD) sub-frameconfiguration without a half duplex FDD limitation, wherein the secondindication is indicated by selection of a second RACH preamble and/or asecond RACH sub-frame location; and generate instructions to performtransmit and receive operations during any of the FDD sub-frames. 11.The apparatus of claim 10, wherein the apparatus co-exists in a cellserved by the base station with at least one user equipment device (UE),wherein the at least one UE does not have a power limitation and isconfigured to communication according to an unlimited sub-frameconfiguration and full duplex frequency division duplex (FD-FDD). 12.The apparatus of claim 10, wherein the power limitation results in alimited radio frequency (RF) range.
 13. The apparatus of claim 10,wherein the power limitation is associated with one or more of: batterycharge state of a battery powering the apparatus; radio conditions; orthermal conditions near the apparatus.
 14. The apparatus of claim 10,wherein the one or more processors are further configured to: transmit,within a subframe allocation based on a RACH configuration used forrandom access, at least a msg3 of a RACH procedure associated with theindication transmitted via the RACH.
 15. The apparatus of claim 10,wherein, to determine the power limitation, the one or more processorsare further configured to: monitor one or more metrics associated withtransmission performance; and determine that at least one metricindicates a need to reduce transmissions.
 16. A non-transitory computerreadable memory medium storing program instructions executable byprocessing circuitry of a user equipment device (UE) to: determine apower limitation at the UE; at a first time, in response to determiningthe power limitation at the UE, generate instructions to transmit anindication to a base station indicating the power limitation at the UEvia a random access channel (RACH) preamble to request a configurationof a limited sub-frame allocation comprising a limited number ofdownlink and uplink sub-frames, wherein the first indication isindicated by a selection of a first RACH preamble and/or a first RACHsub-frame location; generate instructions to perform transmit andreceive operations during sub-frames of the limited sub-frameconfiguration; at a second time, generate instructions to transmit asecond indication to the base station via a second RACH to request aconfiguration of a full sub-frame allocation comprising a frequencydivision duplex (FDD) sub-frame configuration without a half duplex FDDlimitation, wherein the second indication is indicated by selection of asecond RACH preamble and/or a second RACH sub-frame location; andgenerate instructions to perform transmit and receive operations duringany of the FDD sub-frames.
 17. The non-transitory computer readablememory medium of claim 16, wherein the UE co-exists in a cell served bythe base station with at least one other UE, wherein the at least oneother UE does not have a power limitation and is configured tocommunicate according to an unlimited sub-frame configuration and fullduplex frequency division duplex (FD-FDD).
 18. The non-transitorycomputer readable memory medium of claim 16, wherein the powerlimitation results in a limited radio frequency (RF) range for the UE.19. The non-transitory computer readable memory medium of claim 16,wherein the power limitation at the UE is associated with one or moreof: battery charge state of the UE; radio conditions at the UE; orthermal conditions at the UE.
 20. The non-transitory computer readablememory medium of claim 16, wherein the program instructions are furtherexecutable by processing circuitry to: transmit, within a subframeallocation based on a RACH configuration used by the UE for randomaccess, at least a msg3 of a RACH procedure associated with theindication transmitted via the RACH.